Concept of Networking

Concept Of Networking.

You will get idea on the types of topology like, bus, ring, star, extended star, hierchical and mesh topologies. There are several kinds of networks like LAN, WAN, MAN, SAN etc. which you will get an brief idea on these types of networks. You will also know the most important network mathematics which you should be familiar with in order to be network professionals in your life.

At last, I will let you know about the very basic concept of networking, i.e. the reference models (tcp/ip) and OSI Reference models.

Topology Network Types Network Math Reference Models

Let's start with the definition of networking.

Definition: As you have already aware of this term, you can say that two or more systems when have the capability of communicating with themselves, then they became in a network. Just like we are communicating with you people, thus here is a network. You cannot say that networking means only in the term of computer networking. A system means a human being, a house, an organization etc. anything can be a system. Because we are studying only computer networking, here we can say system as computers or some computing related devices. So, networking means the concept of communication between devices and we will deal with this here after.

Reference Models:

Networks are complex environments involves multiple media, multiple protocol interconnection between organizations central office to outside networks. So, there is a complex set of functions that a system has to undergo to have a communication with another system in a network.

To understand this complexity each and every function of the system are separated into several layers. These layers help in building, designing and maintaining networks. This is called reference model. There are two such models that describe the functionality of networked systems.

TCP/IP OSI - Open Systems Interconnection

Layer No. TCP/IP OSI Output

7 Application Application Data

6 Presentation Data

5 Session Data

4 Transport Transport Segment

3 Internet Network Packet

2 Physical Data link frame

1 Physical bits

Application Layer:

This layer provides networking services to upper layer applications. At this point, user/applications interface with protocols to gain access to the network. Example: A word processor served by file transfer at this layer.

Presentation Layer:

This layer provides data representation code formatting and negotiating data transfer syntax between stations. A variety of coding and conversion functions are applied to the application layer data at this layer. Encryption/decryption also happens at this layer. Example: coding of jpg or gif images

Session Layer:

This layer is responsible for establishing, managing, maintaining, and terminating communication sessions between presentation layer entities. Communication at this layer consists of services request and response that occur between applications located at different devices.

Example: type of co-ordination between database server and database client.

Transport Layer:

For communication between two systems connection should be established. This logical connection is done at this layer. The main function of this layer is segmentation/de-segmentation of upper layer data, flow control, windowing, recovery etc.

a) The upper layer data is converted into transport layer data stream called segments. This happens by upper layer application identifiers which is the service access points (SAP). Example, in case of IP protocol it's called port numbers.

b) This layer allows application for reliable data transfer. For IP, TCP is a connection oriented and hence a reliable protocol. The TCP/IP communication is being done by a three way handshake.

Sender receiver

Synchronies ack synchronise

ack (now connection established)

Data Transfer

Network Layer:

This layer defines how to transport traffic between devices that are not locally attached, in the same broad cast domain.

Collision Domain: A group of devices that connected to the same physical media so that, if 2 devices access the media at the same time the result is a collision.

Broadcast Domain: Group of devices in a network that receives one another’s broadcast message.

This accomplished by two of the below things.

Logical addressing - with source and destination stations in the packet.

A Path through the network to the destination.

Thus, the best possible path is determined by this layer.

IP Header Source Address(192.168.1.5)

Destination Address Data

Router operates at this layer.

ICMP: (Internet Control Messaging Protocol)

This is the error reporting protocol in the IP suite. It works in the network layer. When a device tries to send any packet to another device but the packet was no able to reach the destination, the sender receives the message through ICMP packet. Echo (ping) is also an icmp message.

ARP: (Address Resolution Protocol)

For devices to communicate, sending device needs the destination devices IP and MAC. Each system maintains its ARP table which is IP to MAC entry from where the sender can get the MAC addresses. But if the entry is not found in the ARP table it sends a broadcast message to all the devices with MAC as (FFFF-FFFF-FFFF) Every device see this and send this to network layer. If a match found in the network layer, the response packet sends to the source (destination) device.

RARP (Reverse ARP)

This protocol is used to find the IP address of a device when MAC is known. Diskless hosts know their MAC but to know their IP during boot, the send RARP request. An ARAP server resolves the situation.

Router

It's a device which communicates traffic between two or more networks present in a different geographical location. Routers build routing table in their memory and forwards the packet in the port according to the info available in the table.

Routing Table

Net INT Metric1 E0 02 s0 03 s0 13 s1 1Data Link Layer

This layer defines physical transfer of packets across a medium. The physical addressing of data (MAC) is being done in this layer. It has two sub layers.

1. MAC: Media Access Control2. LLC: Logical Link Control

MAC

MAC layer defines how data is transmitted over the physical wire. It encapsulates the MAC address of source and destination to upper layer data. The MAC sub layer frame is as like below:

8 6 6 2 variable 4

Preamble DestAddr SrcAddr Lenght data FCS

IEEE Assigned Vendor AssignedLLC

This layer is responsible for logically identifying protocol types and then encapsulating them to be transmitted across the network. A type code or SAP (Service Access Point) identifies the protocol. The LLC frame looks like as below:

8 6 6 2 Variable 4Preamble DestAddr SrcAddr Length data FCS

MAC Addr

1 1 ½ variable

destSAP

srcSAP Ctrl Data

or

1 1 ½ 3 2 VardestSAP srcSA

PCtrl OU

Itype Data

Example: SAP E0 means: IPX

0000.0C Xx.xxxx

SAP 06 means: IP likewise

Physical Layer

The physical layer defines the media type, connector type and signaling type. It specifies the electrical, mechanical, procedural, and functional requirements for activating, maintaining and deactivating the physical link between end stations.

There are 3 physical layer wiring standards.

10 Base 2 (thin net) 185 meters 10 Base 5 (thick net) 500 meters 10 Base T 100 meters

Collision domain: A group of devices that connect to the same physical media so that if 2 devices access the media at the same time the result is a collision.

Broadcast domain: Group of devices in a network that receive one another's broadcast message.

Another most important thing which need to understand today itself is the three layer model of CISCO which you should know to design a proper network model.

The three layer hierarchical model is as below:

To simplify network design, implementation and management, Cisco uses a hierarchical model to describe the network.

This model has three layers.

1) Access2) Distribution3) Core

Access Layer: This is a point where users connect to the network. (Desktop Layer)

Distribution Layer: This point is between the access layer and the networks core services. Main task of this layer is to perform functions like routing, filtering and wan access.

This layer chooses the fastest way for a user request (such as file server access) to be forwarded to the server. Once, path chosen, it's forwarded to core layer.

Core Layer: (Backbone Layer)

This layer switches traffic as fast as possible to the appropriate service. Example of services like e-mail, internet access, and video conferencing. When a user needs access to enterprises service, the request is processes at the distribution layer. The distribution-layer-device forwards the request to the backbone. The backbone provides quick transport to the service.

The distribution layer provides controlled access to the core.

IP Address, Sub/Super Neting, CIDR, VLSM

IP Address: This is a 32 bit unique number that is assigned to each device in a network. It is separated with 4 octates. Each Octate is of 8 bits.

Example of an IP Address is as below:

192.168.2.51

If we try to represent this in binary form, It will be as below:

11000000.10101000.00000010.00110011

The entire IP Addresses are divided into 5 classes

They are as in the below table:

Class A B C D E

Hi Order 0 10 110 1110 11110

Range 1-127 128-191 192-223 224-239 240-255

Each IP address has two parts:

1. Network Part2. Host Part

In a single logical network the network portion of all the IP addresses is the same where as the host portion varies. Subnet Mask determines which network and host portion of an IP address.

Subnet Mask: It is also a 32 bit number as an IP address and separated by 4 octets. It's of a continuous 1s and 0s. When a subnet mask is anded with the IP address it produces the network number of the logical network.

Example:

IP : 192.168.1.1

Subnet Mask : 255.255.255.0

Anding Result : 192.168.1.0

So the network part is 192.168.1 and the host portion is the last octate (varies from 1 thru 255)

In these networks there will be 254 hosts possible.

If we consider the above class addresses, below table will show number of hosts and

A B C D EnoOfN/Ws 126 16384 2097152NoOfHosts 16777216 65535 254D.SubnetMask 255.0.0.0 255.255.0.0 255.255.255.0

Public and Private IP Addresses

Some portions of the above three classes of IP Address are reserved by IANA-Internet Assigned Numbers Authority (formerly nterNiC=Internet Network Information Center) for addressing an intranet, a test lab, a home network and these are called private addresses.

The table below describes ranges of IP addresses which are private from the above 3 classes.

A B C

10.0.0.0 to 10.255.255.255 172.16.0.0 to 172.31.255.255 192.168.0.0 to 192.168.255.255

Rest of the addresses is public and is assigned in the public internet.

Broadcast Address: If a device wants to broadcast any packet to the network, then in the network layer, the destination IP address has all 1s in the host portion. This is called the broadcast address.

Example: -

A device with C class address as 192.168.10.25 wants to broadcast a packet. The broadcast address it should use in the layer 3 header would be: 192.168.10.255

Similarly, the broadcast address for Class A & B networks would be N.255.255.255 and N.N.255.255 respectively, where N is the octate in the network portion as in the network address.

Subnetting

What is subnetting?

Suppose there is an organization with 4 departments and each department has nearly about 25 employees. You have to design a internal LAN for that office.

Suppose you have assigned a class C address like 192.168.1.0.

So there will be 255 hosts can be assigned to the office which is available in the ip range which you have selected.

Now, You need 25*4=100 ip addresses

But 255-100=155 address spaces will be waist as there will be of no use. But in future if the company grows, then only you can use those address spaces.

When any device try to send a broadcast packet; that will be received by all the devices in the network and there might be chances of too much traffic in the network.

So, to overcome this you can assign IP address to your office in some other way, i.e. breaking the existing class C network to further small networks.

We are breaking a class C network 192.168.1.0

This can be done by burrowing some bits from the host portion of the IP to the network portion. Question is how much bit to be borrowed? In the above question, the host portion has 8 bits.

Let's go through the rules that we should use while dealing with the subnetting.

Rule 1 : Burrow at least 2 bits and leave at least 2 bits.

Rule 2 : No. of usable subnet will be: 2b-2, where b=no. of bits borrowed.

Rule 3 : No. of usable hosts per subnet will be: 2r-2, where r=no. of remaining bits.

Rule 4 : The decimal value of the last bit borrowed is the increment in the network address of that subnet and its 1st usable subnet.

The place value of the bits in the last ocate is as below:

8 7 6 5 4 3 2 1128 64 32 16 8 4 2 1

We have 4 departments, so, we need to have 4 subnets.

Adding numbers from the last till it becomes >= 4, we have

1+2+4=7>=4

So, there are 3 bits from the right we have added.

This means we have to burrow 3 bits from the host portion from left (not right)

Before burrow, the line that separates the ntwork portion to host part as below:

11000000.10101000.00000001. 00000000

Default subnet mask was: 255.255.255.0

After burrowing, the imaginary line moves 3 bits right as below:

11000000.10101000.00000001.000 00000

So, here the subnet mask becomes 255.255.255.224 (224=128+64+32)

Here 3 bits are borrowed, thus no of subnets will be 23 – 2 = 8 – 2 = 6

We have 4 departments and there are 2 more departments for further office use in future.

No. of hosts per subnet will be 25 – 2=32 – 2=30 which fulfils our requirement.

Now, question is what are the subnets and what is the IP address range in the networks.

Let's build the following network table:

As per the 4th rule, the place value of last bit borrowed is 32, so the networks start with 32 differences. The networks will be 0, 32, 64, 96, etc...

Subnet No. Start IP End IP Broadcast IP Usability0 192.168.1.1 192.168.1.30 192.168.1.31 No32 192.168.1.33 192.168.1.62 192.168.1.63 Yes64 192.168.1.65 192.168.1.94 192.168.1.95 Yes96 192.168.1.97 192.168.1.12

6192.168.1.127 Yes

128 192.168.1.129 192.168.1.158

192.168.1.159 Yes

160 192.168.1.161 192.168.1.190

192.168.1.191 Yes

192 192.168.1.193 192.168.1.222

192.168.1.223 Yes

224 192.168.1.225 192.168.1.254

192.168.1.255 No

The broadcast IP is the IP address in which the host portion has all 1s. The broad cast IP is thus one number less that the next subnet. (32) Thus, 192.168.1.31. Thus the IP range will be one number more than the subnet number and one number less than the broadcast IP. Thus, it becomes 192.168.1.1 to 192.168.1.30. Because this is the zero subnet, you cannot use this subnet in your network.

Similarly the last subnet is the broadcast address of class C network, so, that cannot be used.

Subnetting Class B Address

Consider an example IP: 172.16.0.0

Requirement: no. of depts.: 20, users per dept 1000

Bits to be borrowed=1+2+4+8+16=31>=20

No. of usable subnets=25–2 = 32–2 = 30 which is < 30

No. of users per net=212– 2 = 4096 – 2 =4094

Similarly do the subnetting for class A address.

Subnetting Class A Address

Consider an example IP: 10.0.0.0

Requirement: no. of dept: 20, users per dept 1000

Bits to be borrowed=1+2+4+8+16 = 31 >= 20

No. of usable subnets=25–2= 32–2 = 30 which is < 30

No. of users per net=212–2 = 4096–2 = 4094

CIDR (Classless Inter Domain Routing)

This is a method of using the 32 bit IP address and it's subnet mask in the form of prefix notation, in which you have to the prefix which denotes the number of bits in the network portion followed by a slash.

Example: The IP Address 192.168.1.25 with subnet mask as 255.255.255.224 can be written as 192.168.1.25/27, where 27 indicates that 27 bits are in the network portion and the rest in host portion.

Supernetting

Supernetting is a practice of using a bitmask to group multiple classful networks as a single network address. Supernetting and route aggregation are different names for the same process.

Suppose a router has the following entries in its routing table:

IP Address Binary

172.24.0.0/16 10101100.00011000.00000000.00000000

172.25.0.0/16 10101100.00011001.00000000.00000000

172.26.0.0/16 10101100.00011010.00000000.00000000

172.27.0.0/16 10101100.00011011.00000000.00000000

172.28.0.0/16 10101100.00011100.00000000.00000000

172.29.0.0/16 10101100.00011101.00000000.00000000

172.30.0.0/16 10101100.00011110.00000000.00000000

172.31.0.0/16 10101100.00011111.00000000.00000000

Instead of all those 8 addresses in the routing table, the router can have only one address as 172.24.0.0/13 10101100.00011000.00000000.00000000, i.e. subnet mask as 255.248.0.0

This is called super netting or route aggregation which saves a lot of space for the router.

Thus it helps in

1. Reduced number of CPU cycles in calculating routing table.2. Less memory required3. Efficient routing

Consider another example:

Your company needs to address 400 hosts. So considering in a class full way, how many address space you will require?

a) If you need a class B address, it will give you 254 x 254 = 64516 addresses, but 64516 –400=64116 addresses would be wasted.

b) If you need two class C addresses, it will give you 254 + 254 = 508 addresses, but 508–400 = 108 addresses will be wasted.

As in the (b) case, there is a minimal waste of IP address, you might consider this.

Suppose the following addresses you got from your ISP:

207.21.54.0 & 207.21.55.0

In your router, you need to mention two entries, but instead of this, if you aggregate these two addresses into one it will be as below:

207.21.54.0 =11001111.00010101.0011011 0.00000000

207.21.55.0 =11001111.00010101.0011011 1.00000000

Here first 23 bits are same in both the addresses. Hence, it can be represented as below:

207.21.54.0/23

VLSM (Variable Length Subnet Masking)

When an IP network uses more than one subnet mask, then the feature is known as variable length subnet mask and this feature makes us to subnet an existing subnet as per host requirement.

Example

Consider the IP address: 172.16.0.0/16, which is divided into 256 subnets using the /24 mask.

172.16.0.0/16/24 makes 256 subnets

256 subnets

172.16.14.0/24/27 makes 23=8 sub-networks

} 8 subnets

172.16.32.0/27/30 makes again 8 sub-sub nets within one /27 subnet

Each /30 sub network has 2 hosts each and that can be assigned to WAN links.

In this way, network hierarchy can be built.

VLSM Features

1. Efficient IP addressing:2. Route summarization: Instead of advertising a bunch of routes, the summary/aggregate route

has to be advertised, which minimizes overhead3. Route Flapping: If a router goes off and on continuously, this will not affect the entire route as

the other router uses summary address instead of that particular router's address.

EIGRP: Enhanced interior Gateway Routing protocol is a Cisco proprietary routing protocol of the link state type based on IGRP. This is also called hybrid routing protocol as it is based on distance vector and link state features.

Features:

1. Compatible : IGRP and EIGRP2. Metric :

[k1*Bandwidth + (k2 * Bandwidth)/(256-load) +k3*load] * [k5/(reliability+k4)]Where the defaults values for all these k's are:k1=1, K2=0, k3=1, k4=0, k5=0Thus, with the default values it becomes: Metric = bandwidth + delay

3. Hop count :

RIP=15IGRP=255EIGRP=255

4. Automatic Protocol Redistribution

It will work if IGRP is configured in the same router

Example:

EIGRP 2446 IGRP 2446

A B C

10.1.1.0/24 172.16.1.0/24 192.168.1.0/24

D

EIGRP 2446 172.16.1.0/24

Here, configure B as:

B(config)# router igrp 2446B(config-router)# network 192.168.1.0B(config)# router eigrp 2446B(config-router)# network 10.1.1.0B(config-router)# network 172.10.1.0

5. Route Tagging:

If GRP and EIGRP both are configured, then router tags the routes learned, so that it can be identified how it learned (thru eigrp origrp)

Use the following command to see the tag;

Router# show ip route

In IGRP But in EIGRP

I: IGRP/EIGRP (no distinction)

C: directly connected

D: EIGRP router

D Ex: External router learned from EIGRP redistribution

C: directly connected

Note: route tagging can be configured as a number from 0 to 255

Benefits:

1. Rapid Convergence.2. Efficient use of bandwidth.

Updates packets are sent only to the needy (partial, bounded updates)Minimal consumption of bandwidthHello packets interval: in EIGRP: 60 sec if link < 1.544 mbps

5 sec if link > 1.544 mbpsin EGRP: 90 secin RIP: 30 sec

3. Supports CIDR and VLSM4. Protocol Independent Module(PDMs): supports IP, IPX, AppleTalk

EIGRP Tables

EIGRP TablesNeighbor Table

(stores lists of adjacent routers)Topology Table

(Stores route entries to all destination)Routing Table

(stores the best routes calculated by DUAL for destination)

1. Neighbor Address: network layer addressor neighbor router

1. Feasible Distance FD: lowest calculated metric to each destination

for each configured protocol there is a routing table

2. HoldTime: Hello interval X 3 : 2. Route Source: used for external

60 x 3 = 180 sec for low bandwidth 5 X 3= 15 sec for higher bandwidth

routes, via which route

3. SRTT: Smooth round trip timer Average time to send/receive packets

from a neighbor

3. Reported Distance: RD :distance as reported by the neighbor/adjacent router

4. QCnt: Queue Count No. of packets waiting in Q to be

sent to the neighbor router

4. Interface Information:

5. SeqNo: Sequence Number: The number on the last packet

received from neighbor.

5. Route Status1) P: Passive - stable/ready2) A: Active - in process/being

computed by DUAL

How to view the topology table

router# show ip eigrp topology

Other terms

Successor : - the primary route to reach a destinationFeasible successor (FS) : - backup route to a destinationStack in Active State : - I a query is sent to a route and it did not respond within the active time of

180 seconds, the route goes to stuck in active stateResult :-The neighbor is cleared and become active with error msg for that route as

"stuck in active state"

EIGRP Features and Technology

Neighbor discovery and recovery is same as OSPF

How?

hello packets are sent >>>> exchange routing info >>>> establish neighborhoood >>>>converged

(A)-------------------------

/

--------------------------(B)

-[hello] -------------> whoz on this line?

<--------------------------------[update]-

This is B, here is my routing info.

-[ack] -------------> thx 4 d info

-[update] -------------> This is A, here is my routing info.

<--------------------------------[ack]-

thx 4 d info

A<-----------------Converged----------------->B

2. Reliable Transport Protocol.

updates are sent to a reighboring router reliable as in TCP (but without relying on TCP/IP) It's proprietary to EIGRP and used only for update packets and can be uncast and multicast.

3. DUAL FSM

Diffusing Update Algorithm: Finite State Machine

This is an abstract machine used in EIGRP network, to calculate and compare routes by tracking routes advertised by neighbors and using the metric of each route. It guarantee loop free path to destination and successor and feasible successor are calculated by DUAL FSM

4. PDMs. (Protocol Dependent Modules)

EIGRP is modular means it supports routing protocols like IP, IPX, AppleTAlk etc and these are included through PDMs

EIGRP Packets

-----------------

There are 5 types of EIGRP Packets

1 --> Hello

2 --> Ack

3 --> Update

4 --> Query

5 --> Reply

How to configure EIGRP

---------------------------

It's 4 step process

Step 1---- define autonomous system (AS)

Step 2---- indicate networks

Step 3---- bandwidth configuration

Step 4---- enable logging neighbor adjacency change

Syntax

---------

---- Step 1 ----

router(config)# router eigrp auto-sys-num

---- Step 2----

router(config-router)# network netwoknum

---- Step 3----

router(config-if)# bandwidth kilobytes

---- Step 4----

router(config-if)# eigrp log-neighbor-changes

Example

----------

1.4.0.0

(token ring )

|

|

1.1.0.0 |

(X)----------------- |

/ | 2.7.0.0

-----------------(X)---------------

| A /

| --------------(X)

|

|

|

\| 2.2.0.0

|

|

|

|

|

(X)

RouterA(Config)# router eigrp 109

RouterA(Config-router)# network 1.0.0.0

RouterA(Config-router)# network 2.0.0.0

RouterA(Config-router)# ^z

RouterA(Config)# int s0

RouterA(Config-if)# encap frame-relay

RouterA(Config-router)# bandwidth 64

RouterA(Config-router)# eigrp log-neighbor-changes

Bandwidth configuration

-----------------------

1. for NBMS networks

Rules

=========

a) EIGRP traffic shoiuld not xceed the CIR value of VC

b) EIGRP agreegated all over the VCs shold not exceed the access line speed of the interface

c) Bandwidth aallocated to EIGRP on each VC should be eual on both directons

2. for multipoint VC configuration and if all the VCs share bandwidth evenly

bandwidth= sum of all CIRS

example

figure

(X) A

|

|

|

|----------------- CIR 56

/|\ /

/ | \ --------------(X)

/ | \

/ | \

CIR 56 / | \

/ | \ CIR 56

/ |\| \

/|/ | \|\

/ | \

/ |CIR 56 \

/ | \

(X) | (X)

(X)

56+56+56+56=224

So the configuration in the router A should be as below:

interface serial 0

encap frame-relay

bandwidth 224

ii)for hybrid multioint : vcs allocated different speed

you can configure this 2 way

`1 way: bandwidht=lowest vc's CIR * no. of VCs

2 way: use subinterfaces

Example:

(X) A

|

|

|

|----------------- CIR 56

/|\ / BW 56

/ | \ --------------(X)

/ | \

/ | \

CIR 256 / | \

BW 224 / | \ CIR 256

/ |\| \ BW 224

/|/ | \|\

/ | \

/ |CIR 256 \

/ |BW 224 \

(X) | (X)

(X)

In the above case, lowest VC is of CIR value 56, so bandwidth=56*4=224

So configuration in the 1st way would be like as below:

interface serial0

encap frame-relay

bandwidth 224

In Way2, all interfaces are to be configured separately.

256+256+256=768

interface serial0.1

bandwidth 768

...

...

interface serial0.2

bandwidth 56

...

etc.

IP bandwidth percent command

----------------------------

Percentage of bandwidth that can be used by EIGRP can be configured by this. It's normally used if bandwidth setting of the link does not reflect the true speed.

Example:

---------------

interface serial0

bandwidth 32

ip bandwidth-percent eigrp 24 100

^ ^

| |______Percent value

|_________AS Number

NOw the percentage of bandwidth that can be used is 32*100%=32 kbps

EIGRP Autosummarisation

----------------------------

By default, EIGRP summarises at classfull boundary. It means if a router is connected to a subnetwrk it will advertise that network as aclassfull network.

----------(X)___________

2.1.0.0/24 /___________(X)

A B

|

|----->2.0.0.0/8

The subnet address 2.1.0.0/24 is advertised as 2.0.0.0/8 (class A) to B

So, for discontigous networks it should be disabled as below:

router(config-router)# no auto-summary

Manual summarization

-----------------------

router(config-if)# ip summary-address eigrp as_num ip_add sub_mask admin_dist

Example

-------------

router(config)# router eigrp 2446

router(config-router)# no auto-summary

router(config-router)# exit

router(config)# interface serial0

router(config-if)# ip summary-address eigrp 2446 2.1.0.0 255.255.0.0

Troubleshooting/Verification Commands

-----------------------------------------

1. Show ip eigrp neighbors [typeno] [details]

- to display neighbor table

2. show ip eigrp interfaces [typeno] [as no] [details]

- to displa eigrp interface for each interface

3. show ip eigrp topology [as-num] [ipadd [mask]]

- details of feasiable successors

4. show ip eigrp topology [active | Pending | zero-successors]

- topology table depending on keyword used.

5. show ip eigrp all-links

- all eigrp topology

6. show ip eigrp traffic [as num]

- show packets

7. debug eigrp fsm

8. debug eigrp packet

+=========+

+ PPP +

+=========+

Amongst the 3 types of connection type (leased, circuit-switched, packet-switched) PPP falls in the leased line catagory.

Features

===========

non-cisco

multi protocol

authentication

can be synchronous or non synchronous

basic purpose to pack l3 protocol in l2

HOw it works

--------------

For this to function correctly 2 data link protocols are required

1- LCP - Link control protocol

2- NCP - Network Control Protocol

LCP designed to establish, configure, maintain terminet p2p session.

NCP it's designed to establish and configure differentt netwoak layer protocol. Used to pack several network layers protocol (IP, IPX, AppleTalk)

A PPP Session is established in 3 states

1) Link Establishment

-----------------------

LCP packets sent to the other end to configure and test. The packet has all the configuration options in the field

2) Authentication

---------------------------

Once confiured, CHAP or PAP is used for authentication, before network layer protocol

3) Network Layer Protocol

--------------------------

In this phase, the all network layer protocols encapsulated and then sent accross PPP link.

So, what are the main components of a PPP link?

1) EIA/TIA - 232 - C --> This is the physical layer stands for serail communication

2) HDLS - methods of encapsulation data grams over serial link.

3) LCP used for establish, configure, maintain & terminent p2p session/ink

4) NCP Different network layer protocol are encapsulated by this.

Layers | Protocols work

-------------------------------------------

3 | IP, IPX, AppleTalk etc.

---------------------------------------------

2 | NCP

| LCP

| HDLC

---------------------------------------------

1 | EIA/TIA -232

| V.24, V.35, ISDN etc.

So, what are the LCP configuration options

1) authentication: The authentication methods used are PAP, and CHAP

2) compression

3) error detection

4) Multilink

Now, let's come how to configure a PPP link between two routers.

Router A Router B

(X)---------- ----------(X)

/ /

------------(((((O))))))------------

switched n/w

RouterA

---------

RouterA# config t

RouterA(config)#hostname Hyd

Hyd(Config)#Username Blore password cisco

Hyd(Config)#int so

Hyd(Config-if)#ip address 192.168.1.1 255.255.255.0

Hyd(Config-if)#encapsulation ppp

Hyd(Config-if)#ppp auth chap pap

Hyd(Config-if)#no shutdown

RouterB

---------

RouterB# config t

RouterB(config)#hostname Blore

Blore(Config)#Username Hyd password cisco

Blore(Config)#int so

Blore(Config-if)#ip address 192.168.1.2 255.255.255.0

Blore(Config-if)#encapsulation ppp

Blore(Config-if)#ppp auth chap pap

Blore(Config-if)#no shutdown

HOw to test the link?

--------------------------

1) sh interface s0

2) ping from one network to other

3) debug ppp authentication

Remember:

------------

You need to set the password same in both the devices which is case sensitive.

--X--

+=========+

+ HDLC +

+=========+

HIgh level data link control

HDLC is a popular wan link configuration protocol used in leased ines. it's bit orientied protocol wht is bit and byete oriented protocol?

In the frame of dta which has the control infor encloded to configureation wan ink, ttakes the whole byte in byte oriented and the only bit in the bit oriented protocol

Cisco routers are default to HDLC

Similarly each vendor has their won proprietary HDLC frame types and if you use one end CISCO and the other end any other companies router, you can noet used cisco's HDLC instead you need to use PPP.

How to configure?

----------------------

Router# config t

router(config)# int s0

Router(config-if)# ip address 192.168.1.1 255.255.255.0

Router(config-if)# no shutdown

Router(config-if)# encap hdlc

Router(config-if)# clockrate 9600

Router(config-if)# ^Z

Router#

If both side has the same configuration then the link and protocol will come up, unless not.

Testing

-----------

1) ping

2) sh int so

--------X--------------

+================+

+ Frame-Relay +

+================+

Amongst the 3 types of WAN configuration types , framle ralay falls in the packet switch, type .

Insted of getting a leased line with p2p link, we are getting a simillar type of ink but that's shared with other customers, so that, we can get that link to be used only when we need to send data.

As the link is shared, we are not getting the whole bandwidth to use, but the average bandwidth consumed is being allocated to us.

The max speed at which the frame can be transferred is the AccessRate. The only average amount, which the provider can quarrante is only the CIR (commited Information Rate) Transmission exceeding CIR is called burst. Burst packets can be delivered and can't be delivered depending on traffic. If not delivered DTE willbe notified. But packet size exceeding access rate should be dropped

HOw does it work?

---------------.

See the picture below:

[csu/dsu]----------[demarc]------[co]------[demarc]-------[csu/dsu]

| |

| |

| |

| |

(X) (X)

| |

| |

[switch] [switch]

| |

| |

[computer] [computer]

1) User dat comes to the router, ,router picks the frame, extracts the packet, looks the destination address, forward the packet onto the interface as per the routing table.

2)The CSU/DSU received the signals, ,encodes it as needed by the packet switching exchage (PSE). The packet is sent to demarc (POP) which is the first point of responsibility of service provider. The demarc connected to CO through local loop.

3) The CO received the fram and then drops the frame into the frame relay cloud (what's this?) This is dozens of switching offices for the telecom through which the data shold be passed onto is refered as cloud. This is much complicated and we are nothng to worry about it as this is the telecom whoch takes care of this, then it's refered as cloud

4) The frame reaches at the cosed switching office at the destination end, moves to demarcation through local loop, the CSU/DSU then to the router, Routers extract the packet, from the from it received then sends to the destination IP network.

This is the very simple way that a frame relay network works.

Some other things need to be known also.

Virtual Circuit

------------------

As opposed the real circuit, in case of a point to point link in a leased ine, a logical virtual circuit is established between the source and destination thru the frame relay cloud. which can be permanet (PVC) or temporary/switched (SVC) SVCS occur when data transfer is required, a callis placed before the actual transfer, link establies, and after data transfer, the ink closed/terminets.

So, a router having only one serial interface can be connected to 3 or morebranches at a time by using vertual circuits in a single link.

(X)------------(X)-----------(X)

|

|

|

|

(X)

Serial Lnk

(X)

|

|

|

|

(X)------(((frm-rly cld))))---------(X)

|

|

|

|

(X)

frame relay cloud

So, when router receives a packet, to send to a particlar branch it needs to select to which PVC it should frorward to. Here, DLCIs data link connection Identifiers help the routers to select the appropriate PVC. So,what are DLCIs?

DLCI

---------

Frame-relay PVCs are identified by a DTE by using the DLCIs. In CISCO routers there is IARP table, which mmaps IP to DLCI which router checkes before forwarding to a particular PVC

HOw to view that table?

router#show frame-relay mapThen

There is no IARP in non-cisco routers. So, you need to configure it mannually, how?

like this, see....frame-relay map command got?

LMI

-----------

Local Management Interface

It's just a signaling standard from the first frame relay switch to the router. Information related to status of VC and it's operation is passed between the frame-relay switch and the router.

i) keepalives - to veryfy data flow

ii) multicast (optonal) distribution of routing info, ARP request using DLCI (1019 to 1022)

iii) Global Addressing: Provides global significance to DLCIs (Ths frame relay could bbehaves like a local lan.

What is global significance and local significance of DLCI ?

See, router A checks it's IARP database for DLCI to forward the packet to a perticular PVC, which goes to a frame relay switch. Then, the frame rela switch looks its own IARP to find to DLCI ti its next switch. The router DLC do not know this, thus the routers DLCI is locally significant, got?

To make the DLCI globally significant, LMIs should be configured accurately.

iv) Status of VCs: Regular status messages are used as keep alives to make the connnection alive.

There are 3 different LMI message formats

1) CISCO, 2) ANSI 3) Q.933A

RouterA(config-if)Frame-relay lmi-type

CISCO

ANSI

Q.933A

RouterA(config-if)

So, router received the lmi status infor from switch and then respondes the status or state, okay?

These states are:

acive- everything is up, fine

inactive - interface is up, but remote router not working

deleted - no lmi infor received mapping problem or lmi failuree

Congestion Control

-----------------

So beyond CIR, data transdfer is a risk, fear of toast, burst ! right?

So, when to tansfer, beyound CIR? HOw to know that the telco's infrastructure is free?

Ys, telco's switch informs your DTE (router)

How?

in the frame header of teh packet several bits are used to identify congestion in the providers network.

1-DE -Discard Eligibility

Data packets beyond cir have de bit set to 1 means if the providers network is congested, data can be discarded.

2-FECN- forward explicit congest notification

The frame-relay switch set the FECN bit 1 to informa the destination router that the path the frame just transferd is conjested.

3-BECN- Backward explicit Congested Notification

The frame relay switch sets this bit on and sends to the source router that network is conjested (if you configure cisco router accordingly it can be understood that bit, unless not)

how to traoubleshoot with PVC

router#whos frame-relay pvc

So, ready to confirure frame-relay?

RouterA# config t

routerA(config)# int s0/0

routerA(confgif-if) encap frme-relay

routerA(confgif-if) ip address 192.168.1.1 255.255.255.0

routerA(confgif-if) frame-relay lmi-type ansi

routerA(confgif-if) frome-relay interface-dlci 101

routerA(confgif-if) ^z

RouterA#

The lmi-type and interface-dlci are provided by the provider.

Then how to configure sub interfaces also

RouterA# config t

routerA(config)#int so

routerA(config-if)#encap frame-relay

routerA(config-if)# int s0.16 point-to-point

other type of subinterface is point-to-multipoint

NOte: In a point to point subinterface, the subinterface should have separate subnets but in a multipoint, all the subinterfaces shold have the same ip subnet.

So, now we are done with configuring a frame-relay network.troubleshoot??

some must known commands

show frame ? (lmi, map etc)

show interface so

show debug frame-relay lmi etc.

ISDN

=================

What is ISDN?

ISDN is a set of communication protocol, which are designed to carry data of various types including, video, voice, over the existing telecommunication link.

Before discussion further let's discuss some fundamental equipment needed for this connection.

Let me explain you the equipment you need for an ISDN connection.

See, there are 3 types of routers, which you can use for ISDN connections from any ISDN providers.

1.TE1 (Terminal Adapter type 1) This type of router or device can understand the ISDN standards. So, to connect this type of device to the ISDN switch, only a NT1 box is needed. The NT1 box is to be connected to the ISDN switch. The port (Interface)TE1 type of router has is called S/T type of interface.

2.TE2 (Terminal Adapter type 2) This type of device/router was modeled before ISDN type of connection existed. So, they have no such port to connect to the ISDN networks. But you can connect them to the ISDN switch by using an terminal adapter (TA). The TA connects to the NT1 type of NT box which have the S/T port which you can use to connect to ISDN switch. The interface the TE2 type device has R interface.

3. TE1 with NT1 inbuid: As TE1 can understand the ISDN standard and if it has the NT1 box inbuild, then there is no need of any other NT box for this type of router. These type of devices/routers can be connected to the ISDN switch directly and there is no need of any additional equipment in between. This type of device have U interface.

NT1 or NT2 box:

These are Network Termination boxes, purpose?? Yes, ISDN provided connection in 2 wires as like as the telephone network, but these NT boxes convert the 2 wire signal into 4 wire (UTP standard).

So, what is NT1 and NT2, why two??

NT1 is a physical layer implementation and NT2 is a datalink and network layer implemention. That's the difference. Got??

So, in TE2 type of device, there is a TA device, used, what is it's purpose?

Yes, this Terminal Adapter, is used, becoz it will convert the signal type of the TE2 type device so ISDN standard which can connect to the NT1 box and can get ISND connection. Got?

So, till now, there are 4 different type of reference points, you have come accross, in these above devices.

What are they?

S

T

R

U

It's true == Pronouce it how?? es tru=STRU

So,

S= defines the reference point, between cuStmer's router and an NT1 box.

T= defines the reference point, between NT1 box and NT2 box.

R= defines the reference point, between Non-ISDN equipment (TE2) to TA.

U= defines the reference point, between ISDN compatible router to ISDN switch.

So, are you clear about the deference device types you need for an ISDN connection?

Okay.

Let's come to the protocols that help in the ISDN connection standard.

Hey! there are so many protocols man!! How can you deal with all them?

So, I will just let you know only some common types of them.

Some starts with E, some I and some other with Q. What are the difference?

The E........s are to deal with existing ISDN network.

The I........s are to deal concepts, aspects, and services of ISDN network.

The Q........s are to deal with switching and signaling. No need to learn more than this.

Hey! when you configure the router for any ISDN switch connection, you need to specify the switch type. Of course the provider will let you know the switch type you need to configure. But you must be aware of the switch types which your router should support.

So, what are the switch types:

They are as below:

1) AT&T basic rate switch basic-5ess

2) Nortel DMS-100 basic rate switch basic-dms100

3) National ISDN-1 switch basic-ni

4) AT&T 4ESS (ISDN PRI only) primary-4ess

5) AT&T 5ESS (ISDN PRI only) primary-5ess

6) Nortel DMS-100 (ISDN PRI only) primary-dms100

How to configure and other things, I will let you later.

Okay?

Just for now,let's come to study the ISDN types.

Hello Dude!!

There are two type of ISDN connection. Means, the ISDN service is provided to customers (you) in two standards.

1) BRI and the other one is

2) PRI

BRI=Basic rate Interface.

This means Basic, basic requirement to fulfill. Minimal data transfer.

Okay?

So, it has three channels in it. 2B + 1D.

2b=Two Basic channels (64KB each) are to send data and 1 D channel (16KB) to signalling (read dialling) and/or controlling purpose.

To total bandwith=64+64-16=144

Note: The D channels has nothing to do with the data transfer, it works with LAPD at the Data Link layer only to reliable data transfer.

PRI=Primary Rate Interface

In case of PRI, there are 24 channels for a T1 link and 30 channels for a E1 link. T1 and E1 are the type of link you subscribe from your provider.

For an T1 link, total bandwidth=24 x 64=1536=1.5 Mbps link (1.544Mbps some book says)

for an E1 link, total bandwidth=30 x 64=1920=1.9=nearly 2 Mbps speed you can get. (2.048Mbps some book says)

One more thing you need to know before configuring BRI on your router.

That's SPIDs: Service Profile Identifiers (One service profile for each channels. In Bri there are 2 channels, so two SPIDS are needed. These are provided by the providers which you need to configure on the router.

But what are these SPIDs?

As the name indicates, SPIDS=Service Profile Identifiers, these are the numbers, configured in the ISDN switch by the providers, which you need to configure on your routers. before you sent any data packet through an ISDN link, connection will be identified by the ISDN switch to validate the link. In other words, without an SPID number the ISDN switch can not validate the connection hence the no call can be placed on the link. Think this of the type of a telephone number. Okay??

To setup a call in the ISDN network, there are 4 events happens.

1) The router to ISDN switch: The local router established a call with the local ISDN switch, hence the channel between the router and the local ISDN switch comes up.

2) ISDN Network Communication: The channel from the ISDN switch to the remote ISDN switch is being activated, made to up, by SS7 Signaling technique.

3) The Remote ISDN switch to remote Router of your company: The remote ISDN switch established a call to your companis remote router.

4) B channes work to transfer data: Now, the total channels ready to transfer data from your local router to remote router and now, B channel is ready to transfer Data.

So, clear about the things you need to configure the ISDN connection on your router?

Suppose you brought ISDN connection from BSNL (as example) what are the things BSNL will provide you to configure on the router? (You can find the manual?)

1) SPIDs: One for each channel. (ex: 086506610100)

2) ISDN switch type

Come on......

Let's configure our router for a ISDN connection in Hyderabad and Bangalore, the ISDN provider is BSNL (suppose).

the following things provided by BSNL.

1) SPIDs: One for each channel.

(1: 086506610100, 2: 086506620100 for Hyderabad)

(1: 086506630100, 2: 086506640100 for Hyderabad)

2) ISDN switch type: National ISDN-1 switch (basic-ni)

Hyderabad#config t

Enter configuration commands, one per line. End with CNTL/Z.

Hyderabad(config)#isdn switch-type basic-ni

Hyderabad(config)#int bri0

Hyderabad(config-if)#ip address 192.168.1.10 255.255.255.0

Hyderabad(config-if)#encap ppp (optional)

Hyderabad(config-if)#isdn spid1 086506610100 8650661

Hyderabad(config-if)#isdn spid2 086506620100 8650662

The same settings should be there at the other end in Bangalore. Okay??

Hyderabad#config t

Enter configuration commands, one per line. End with CNTL/Z.

Bangalore(config)#isdn switch-type basic-ni

Bangalore(config)#int bri0

Bangalore(config-if)#ip address 192.168.1.11 255.255.255.0

Bangalore(config-if)#encap ppp (optional)

Bangalore(config-if)#isdn spid1 086506630100 8650663

Bangalore(config-if)#isdn spid2 086506640100 8650664

The switch type in the above example is configure in the configuration mode. If you configure that in global configuration mode, then all the Bri interfaces will automatically take that configuration and you need not specify them once again, as

above.

The second part of the SPID configuration is the local dialer, this is used when you try to use both the channels at a time.

One more thing you need to understand.

DDR=Dial On Demand Routing for interesting traffic.

===================================================

You are the Network Administrator of company ABC Corp. You have branches of your company at Bangalore, Head Office at Hyderabad. you have already setup ISDN connection at both the end.

Okay??

Most of the time there is no need of sending any data between the branches and some times you need to send some important data between branches.

or you can say that you need to use the ISDN connection for some important time only and for the other time, there is no need to send any data between branches.

Then what you need to do?

You need to configure the data on your router as interesting traffic and when the router judges a packet for interesting, then only it calls the ISDN switch and sets up the call and forwards the traffic. Other packets if a call is already established, then can be passed by the route. If no call is established, then no call will be setup for the other packets.

In this case, you need to pay the provider only for the time you use or for the packets you travel.

Really Good na??

So, how to proceed.

Let's check again how DDR works.

Following steps are to be followed by an interesting traffic.

1) Interesting traffic reaches at the router.

2) Router determines the destination.

3) The interesting packets dictates a DDR call.

4) The dialer INformation is looked up in the database.

5) The call is placed.

6) packet transfermed.

7) CAll terminated when there is no more data to transfer.

So, let's configure DDR.

To configure DDR, you need to go with the follow steps:

1) Configure static route, why???: Because, if you configure dynamic route, the call will be never drop.

2) Specify interesting traffic.

3) Configure the dialer information.

1) Configure static route.

Hyderabad(config)#ip route 192.168.1.11 255.255.255.0 192.168.1.2

2) Specify interesting traffic.

Hyderabad(config)#dialer-list 1 protocol ip permit -------> defines the accesslist (interesting packet)

Hyderabad(config)#int bri0 -------> in global config mode.

Hyderabad(config-if)#dialer-group 1 -------> set's the access-list to the Bri interface.

3) Configure the dialer information.

There are five steps in the configuration of the dialer information.

1. Choose the interface.

2. Set the IP address.

3. Configure the encapsulation type.

4. Link interesting traffic to the interface.

5. Configure the number or numbers to dial.

Here is an example of how to configure the five steps:

804A#config t

804A(config)#int bri0

804A(config-if)#ip address 172.16.60.1 255.255.255.0

804A(config-if)#no shut

804A(config-if)#encapsulation ppp

804A(config-if)#dialer-group 1

804A(config-if)#dialer string 8350661

So, now, everything is done!!

Then, how to see, if you have done everything correctly or ....??

1) Router#show run

2) ping, teltet --> to test router signal

3) show isdn status -->status of ISDN, if valid, SPIDs or not

4) show dialer --> dialer diagnostic information.

5) show isdn active --> show the number called, and the progress

6) show ip route --> shows the routes the router knowns about.

7) debug isdn q921 --> to see layer2 info

8) debug isdn q931 --> to see layer3 info (including callsetup, teardown etc)

9) debug dialer -->callsetup, teardown activity.

X.25 Back-to-Back Connections

Document ID: 7921

Introduction

=============

This document provides a sample configuration for X.25 back-to-back connections. You can use it to verify that your connections and hardware are working properly.

Prerequisites Requirements

==================================

Readers of this document should have a basic understanding of the following:

X.25

TCP/IP

Components Used

==================

The information in this document is based on the software and hardware versions below.

This configuration is applicable to all Cisco IOS® Software Releases. All the routers (Cisco 2500 Router) in this document use Cisco IOS Software Release 12.2(10b).

The DCE side of the X.25 connection is connected with a WAN DCE cable.

The DTE side of the X.25 connection is connected with a WAN DTE cable.

For more information on WAN DCE and DTE cables, refer to Serial Cables.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

==============

For more information on document conventions, see the Cisco Technical Tips Conventions.

Configure

==========

In this section, you are presented with the information to configure the scenario described in this document.

Note: To find additional information on the commands used in this document, use the Command Lookup Tool ( registered customers only) .

Network Diagram

=====================

This document uses the network setup shown in the diagram below.

Router(DCE) at Prasit (s0) --------------

/

-------------(s1) Router(DTE) at Spicey

The default serial encapsulation is Cisco High-Level Data Link Control (HDLC). You must explicitly configure the X.25 encapsulation method using the encapsulation x25 command. The dce option specifies operation as a logical X.25 DCE device.

On a back-to-back serial connection, the router with the DCE end of the cable acts as the physical layer DCE and provides the clocking signal for the line. The clock rate command in the interface configuration mode enables the router at the DCE end of the cable (Prasit, in this example) to provide the clocking signal to the line.

Note: Any of the above two routers can act as logical X.25 DCE device, irrespective of which end of the cable is connected to the router. In other words, the encapsulation x25 dce command can be placed in either one of the above two routers.

Configurations

This document uses the configuration shown below. In this configuration, Prasit acts as both physical layer and X.25 DCE, and Spicey is the physical layer and X.25 DTE.

Prasit

Spicey

Prasit

interface Serial0

ip address 5.0.2.1 255.255.255.0

encapsulation x25 dce

!--- Specifies a serial interface's

!--- operation as an X.25 DCE device.

x25 address 7890

!--- Sets the X.121 address.

x25 map ip 5.0.2.2 1234

!--- Sets up the LAN protocols-to-remote

!--- host mapping.

clockrate 64000

!--- Specifies a serial interface's operation

!--- as a physical layer DCE device.

no cdp enable

Spicey

interface Serial1

ip address 5.0.2.2 255.255.255.0

encapsulation x25

!--- Specifies a serial interface's operation

!--- as an X.25 device. Default X.25

!--- encapsulation mode is "dte".

x25 address 1234

x25 map ip 5.0.2.1 7890

no cdp enable

Verify

This section provides information you can use to confirm your configuration is working properly.

Certain show commands are supported by the Output Interpreter Tool ( registered customers only) , which allows you to view an analysis of show command output.

show controllers serial—Displays information about the interface hardware and the attached cable. Refer to the Command Reference for more details.

ping—Checks host reachability and network connectivity. Refer to the Command Reference for more details.

show x25 vc—Displays information about X.25 SVCs and PVCs. Refer to the Command Reference for more details.

show interfaces serial—Displays information about the interface characteristics, such as encapsulation, bandwidth and other details. Refer to the Command Reference for more details.

The output shown below is a result of entering these commands on the devices in this sample configuration.

Use the show controllers command to check that Prasit is the physical layer DCE and Spicey is the physical layer DTE. This command gives you information on whether or not the physical layer is working and what type of cable is connected.

prasit# show controllers serial 0

HD unit 0, idb = 0x1D3A2C, driver structure at 0x1DAFE8

buffer size 1524 HD unit 0, V.35 DCE cable, clockrate 64000

!---Output suppressed.

spicey# show controllers serial 1

HD unit 1, idb = 0x153E94, driver structure at 0x15A1F8

buffer size 1524 HD unit 1, V.35 DTE cable

!---Output suppressed.

To verify the X.25 back-to-back configuration, use the following steps.

Ping from the X.25 DCE (in this example, Prasit) to the X.25 DTE (Spicey).

In this case, SVC1 is used, the lowest one configured by default.

prasit# ping 5.0.2.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 5.0.2.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 36/38/48 ms

prasit# show x25 vc

SVC 1, State: D1, Interface: Serial0

Started 00:00:07, last input 00:00:07, output 00:00:07

Connects 1234 <-> ip 5.0.2.2

Call PID cisco, Data PID none

Window size input: 2, output: 2

Packet size input: 128, output: 128

PS: 5 PR: 5 ACK: 4 Remote PR: 5 RCNT: 1 RNR: no

P/D state timeouts: 0 timer (secs): 0

data bytes 500/500 packets 5/5 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0

prasit# show interfaces serial 0

Serial0 is up, line protocol is up

Hardware is HD64570

Internet address is 5.0.2.1/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation X25, loopback not set

X.25 DCE, address 7890, state R1, modulo 8, timer 0

Defaults: idle VC timeout 0

cisco encapsulation

input/output window sizes 2/2, packet sizes 128/128

Timers: T10 60, T11 180, T12 60, T13 60

Channels: Incoming-only none, Two-way 1-1024, Outgoing-only none

RESTARTs 1/0 CALLs 2+0/0+0/0+0 DIAGs 0/0

LAPB DCE, state CONNECT, modulo 8, k 7, N1 12056, N2 20

T1 3000, T2 0, interface outage (partial T3) 0, T4 0

VS 5, VR 5, tx NR 5, Remote VR 5, Retransmissions 0

Queues: U/S frames 0, I frames 0, unack. 0, reTx 0

IFRAMEs 29/29 RNRs 0/0 REJs 0/0 SABM/Es 0/1 FRMRs 0/0 DISCs 0/0

Last input 00:00:13, output 00:00:13, output hang never

Last clearing of "show interface" counters 00:22:38

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

33 packets input, 2679 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

42 packets output, 2693 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up

prasit#Then ping from the X.25 DTE (Spicey) to the X.25 DCE (Prasit).

spicey# ping 5.0.2.1



!!!!!


spicey#

spicey# show x25 vc



Connects 7890 <-> ip 5.0.2.1

Call PID ietf, Data PID none





data bytes 500/500 packets 5/5 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0

spicey# show interfaces serial 1

Serial1 is up, line protocol is up

Hardware is HD64570

Internet address is 5.0.2.2/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation X25, loopback not set

X.25 DTE, address 1234, state R1, modulo 8, timer 0

Defaults: idle VC timeout 0

cisco encapsulation

input/output window sizes 2/2, packet sizes 128/128

Timers: T20 180, T21 200, T22 180, T23 180

Channels: Incoming-only none, Two-way 1-1024, Outgoing-only none

RESTARTs 1/1 CALLs 0+0/2+0/0+0 DIAGs 0/0

LAPB DTE, state CONNECT, modulo 8, k 7, N1 12056, N2 20

T1 3000, T2 0, interface outage (partial T3) 0, T4 0

VS 5, VR 5, tx NR 5, Remote VR 5, Retransmissions 0

Queues: U/S frames 0, I frames 0, unack. 0, reTx 0

IFRAMEs 29/29 RNRs 0/0 REJs 0/0 SABM/Es 1/0 FRMRs 0/0 DISCs 0/0

Last input 00:01:10, output 00:01:10, output hang never

Last clearing of "show interface" counters 00:23:59

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

42 packets input, 2693 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

32 packets output, 2657 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

2 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=upUse the following command to clear the X.25 connection on Serial1 of Spicey:

spicey# clear x25 serial 1

Force Restart [confirm]After clearing the X.25 connection, try to ping from the DTE (in this example, Spicey) to the DCE (Prasit).

In this case, SVC1024 is used (the highest one configured).

spicey# ping 5.0.2.1



!!!!!


spicey# show x25 vc



Connects 7890 <-> ip 5.0.2.1

Call PID cisco, Data PID none





data bytes 500/500 packets 5/5 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0Use the same commands again on Prasit.

prasit# ping 5.0.2.2



!!!!!


prasit# show x25 vc



Connects 1234 <-> ip 5.0.2.2

Call PID ietf, Data PID none





data bytes 500/500 packets 5/5 Resets 0/0 RNRs 0/0 REJs 0/0 INTs 0/0Troubleshoot

There is currently no specific troubleshooting information available for this configuration.

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