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Ethernet Operational mode 2+0 VLAN Port Segregation
Fig. 2 Ethernet Payload for Fast Ethernet
With "Auto Negotiation" Disable is possible to choose the port speed (10 or100Mbs) and the Port Duplex mode (Half or Full).
"STP status" (Enable or Disable): it must be enabled to avoid loops in the frametransmission. Loops are present when one NE is connected to another NE by morethan one path (i.e. in Ring Configuration or in mesh network.
"Bridge Priority" (Root / Normal / Backup): if the STP has been enabled, one NEmust be configured as “Root”, all the other NEs as “Normal”. In case of failure of theRoot NE, the NE configured as “Backup” (if any) will replace the Root NE.
"Ethernet Operation Mode": this field is shown only in case of East/Westconfiguration.
In this case the following selections are available:
• 2+0 Normal: this mode is the standard mode of Ethernet operation. Traffic from theEast link, West link, and the front panel ports is switched using the equipmentinternal switch;
• 2+0 VLAN Port Segregation: this mode creates two internal VLANs, each oneforming one group:
• Group 1 = Port 1 associated to East Modem (Lower).
• Group 2 = Port 2 associated to West Modem (Upper).
This allows the user to maintain two separate networks, one on the East link, and oneon the West.
The Quality of Service is a group of parameters to be set in order to differentiate thetraffic between Ethernet ports using a priority configuration scheme
For each Ethernet user interface (Port1 or Port2) the following priority criteria areapplied:
• Port-base
• 802.1Q VLAN TAG priority
• IPv4 ToS priority
The "QoS configuration" Menu is reported in Fig. 3.
• 2+0 VLAN Port Segregation: this mode creates two internal VLANs, each oneforming one Group:
Group 1 = Port 1 and 2 associated to the Lower Modem.
Group 2 = Port 3 and 4 associated to the Upper Modem.
Port 5 (SFP port) can be associated to Group 1or Group 2.
This allows the user to maintain two separate networks over the 2+0 East/East Link;
• 2+0 Trunk Port: this mode allows for higher network throughput via “trunking” twomodems together. Layer 2 MAC addresses are used to perform load balancingbetween modems, therefore utilization of full throughput is dependent upon traffic.
• 4+0 Master: not supported.
EAST/WEST configuration
Ethernet Operation Mode:
• 2+0 Normal: this mode is the standard mode of Ethernet operation. Traffic from theEast link, West link, and the front panel ports is switched using the IDU’s internal
switch;• 2+0 VLAN Port Segregation : this mode creates two internal VLANs, each one
forming one group:
Group 1 = Port 1 and 2 associated to East Modem (Lower).
Group 2 = Port 3 and 4 associated to West Modem (Upper).
Port 5 (SFP port) can be associated to Group 1(East Modem) or to Group 2 (WestModem).
This allows the user to maintain two separate networks, one on the East link, and oneon the West
The following SFP parameters are displayed only if an SFP module is installed:
• SFP Vendor Name – Displays the SPF vendor name
• SFP Link Type – Optical / Electrical
• Set the following Parameters for the SFP module:
• Auto-Negotiation - Enable / Disable
• Port Speed – 10 / 100 / 1000
• Port Duplex – Half / Full
• Flow Control – Disable / Symmetric / Receive Only / Transmit Only
• Master-Slave – Slave / Master / Auto
• Restart Auto-Negotiation: to activate the restart of the auto-negotiation
• Shutdown on Link Failure: to activate the shutdown of the Ethernet port followinga radio link failure to avoid the flooding. After the restoring of the radio link, theEthernet port automatically will be activated.
• SFP VLAN Group: Group 1/Group 2:
• Group 1 is associated to the Lower Modem (East);
The use of this feature is when some components in a network are faster than others.The element in overload will receive a pause frame in order to balance the traffic,(symmetric option).
2.2 Quality of Service
The basic function of the Quality Of Service are the same as chapter 1.2 with somedifferences. The following criteria are now available:
"QoS Global Configuration" for the Port Priority is as follow:
Fig. 15 QoS Global configuration Port Priority Gigabit Ethernet
The system can support a Weighted Fair Queuing (WFQ) scheduling mode with
configurable weights from 1 to 49. The default Priority Queue Weight is 1-2-4-8. Thismeans that the port with High priority will have a Data rate eight (8) time grater thanport with Low Priority
With this solution, the LAN with the highest priority in Port TAG or DiffServ, takes allthe Data rate on air, until the service is delivered before starting to serve the lowerpriority queue. High Queue Preempt is set in the QoS Global Configuration.
Fig. 21 High Queue Preempt Gigabit Ethernet
WARNINGWith this option the Priority Queue Weights are not valid
The Setting in QoS Global configuration is the same as Fig. 21. The LAN port withHigh priority (SPF in the example) is serviced until it is empty before starting to servethe lower priority queue
The screen, shown below, enables the user to assign the priority to the 2 Ethernetinterfaces present on the front panel of the unit (each port can be associated to a Txqueue). The parameters listed on this page are:
• Port Priority – Enter for each Port, the priority (0 = Low; 3 = High).
It is possible, per each available port, to configure the Default VLAN ID assigned tothe port. The Default VLAN ID is the value inserted in the VLAN tag added by theFlexiHybrid IDU. By default all ports are associated to the DEFAULT group withVID=1.
The p-bit value to be used in the added tag is user configurable too. Note that theuser cannot modify the p-bit in the tag that is already present in the ingress frame(replacement is not supported).
4.1.1.2 P-bit configuration aspects
In the GigE and EnhGigE implementation the value of the p-bit is determined on thebase of the Port priority value and can not be independent. Note that the Web-LCTGUI automatically aligns the port priority value to the p-bit value and vice versa, whenthe user change one of the two parameters.
In other modules (42E1, Standard2, Enhanced2) the default port p-bit can bespecified by the user
The user can configure, per each Front Panel Port, which frame type can be admitted
to the switch:
Note : Radio ports are always configured as “Admit all” (no user configurable).
Fig. 34Ingress Policy
4.1.1.4 Egress Policy
On the egress side (frames that are leaving the Ethernet switch), in case of VLANManagement is Single tag it is possible for the user to configure if the tag shall bepreserved or removed using the Egress Policy configuration. This configuration isavailable for the Front Panel Ports only.
Note: For the Radio ports the value is automatically set to “Don’t Remove” and it is not user configurable.
When VLAN Management is equal to Double Tag (“Double Tag (Stag + Ctag) ” or“Double Tag (Ctag + Ctag)”) a different parameter is available to the User, it is herenamed “Port DoubleTag Mode”. It is configurable for each Front Panel Port and Fig.37contains the description of the possible values.
Note that also the Egress policy is configured with the Port Double Tag Mode
The tagging or un-tagging management of frames entering the switch is not explicitly
user configurable but it is implicitly defined by the VLAN Management parameter. Fig.38 summarizes the applied Ingress frame manipulation for each configuration.
(5)Note that this case should not happen if the network is properly configured because the packets enter the
transport network via a User port and consequently at each network port they have already been tagged with the
proper tag.
Fig. 38 Ingress frame Manipulation in Double Tag mode
Applying the above mentioned tables the behavior across a radio link is describedhere below in Fig. 39
Double tag (Stag + Ctag) mode: frame formats at both User and Network ports
Double tag (Ctag + Ctag) mode: frame formats at both User and Network ports
Fig. 39
The cases above can be easily extended also to the cases where the NE is inEast/West configuration.
4.1.2.1 Egress Policy
When the VLAN Management is double tag the egress policy is not configured via adedicated parameter but it is automatically determined on the base of the PortDouble Tag Mode configuration.
If the port has been configured as “Network” its egress policy is automatically
configured to “Don’t Remove”.
If the port has been configured as “User ” its egress policy is automatically configuredas “Remove”.
In the GigE and EnhGigE implementation the value of the p-bit is determined on thebase of the Port priority value and can not be independent. Note that the Web-LCTGUI automatically aligns the port priority value to the p-bit value and vice versa, whenthe user change one of the two parameters.
In 42E1, Standard2 and Enhanced2 Master modules, when QoS criteria differentfrom p-bit criteria, it allows p-bit of the incoming frames to be overwritten; moreoverthe p-bit value can be changed on the base of the type of crossed ports and otherenable criteria. The behavior is here summarized:
In Single tag Mode
• When Port Based or DiffServ criteria are enabled the original p-bit of the incoming
frame are overwritten by the equipment.
• When only the p-bit based criterion is enable the behavior is correct (p-bit of thetagged frames are preserved, untagged frames are tagged with the default p-bitconfigured for the incoming port.
In Double Tag (Stag + Ctag) or Tag (Ctag + Ctag) mode
• At the egress of the transport network the original frame format (i.e.: the p-bit valueof the tag or tags) is correctly preserved in any combination of QoS criteriaenabling.
• When only port based QoS is enable: the p-bit value of the added outer tag ischanged at each port by assigning the default p-bit of the ports the frames gothrough.
• When only p-bit based QoS is enable: the p-bit value of the added outer tag canbe the copy of the inner one or the default value of the port p-bit.
• When DiffServ based QoS only is enable o If the ingress frames are IPv4/IPv6Untagged or C-tagged the value of p-bit is determined on the base of the selectedTX output queue and consequently they are a sort of re-mapping of the DiffServvalue. o Otherwise the value of p-bit is changed at each port according to thedefault p-bit priority assigned to the ports.
4.1.5 Quality of Service management
The following table lists the QoS classification criteria that can be applied for eachVLAN Management mode. When the VLAN Management is different from disable theQoS classification criteria take into account the outer VLAN tag value (the tag islogically added on the base of the ingress port and it is added before the QoSclassification).