Spanning-Tree 31- Introduction 32- MSTP 33- PVST and RSTP 321- Cisco as Core, ProCurve as Edge 322- ProCurve as Core, Cisco as Edge Introduction Glossary STP is Spanning-Tree Protocol The IEEE standard implementation of STP is 802.1D. RSTP is Rapid Spanning-Tree Protocol defined by the 802.1w IEEE standard. MSTP is Multiple Spanning-Tree Protocol defined by the 802.1s IEEE standard. PVST is Per VLAN Spanning-tree proprietary implementation of STP on Cisco equipment PVST+ is the implementation of PVST on 802.1q links. Spanning-Tree on HP ProCurve Switches 802.1D and 802.1w (RSTP) All HP ProCurve switches implement both of these STP standards. On HP ProCurve, Spanning-Tree has to be activated, the default mode is then Rapid STP. MSTP 802.1s It is supported on most manageable switches except 2500 and 4100 switches Please refer to switch documentation. Spanning-Tree on Cisco Switches PVST+ By default, Cisco switches run PVST+. PVST is the implementation of STP on ISL links (Cisco proprietary multi-VLAN encapsulation) while PVST+ runs on 802.1q links . In PVST+, there is one instance of STP per VLAN and BPDUs use a proprietary Multicast Mac Address. They are not “understood” by HP ProCurve switches (except by ProCurve 9300M and 9400M) and are then flooded as a regular multicast. So, regarding PVST+ BPDUs, HP ProCurve switches appear as a hub. However, Native VLAN (untagged VLAN of a tagged link equal to VLAN 1 be default) is an exception. In Native VLAN, the Cisco switches send standard STP BPDUs, which are “understood” by HP ProCurve switches. This is how both platform interact.
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Cisco - ProCurve Interoperability · 2017-08-18 · Spanning-Tree 31- Introduction 32- MSTP 33- PVST and RSTP 321- Cisco as Core, ProCurve as Edge 322- ProCurve as Core, Cisco as
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Spanning-Tree31- Introduction32- MSTP33- PVST and RSTP
321- Cisco as Core, ProCurve as Edge 322- ProCurve as Core, Cisco as Edge
Introduction
Glossary
STP is Spanning-Tree ProtocolThe IEEE standard implementation of STP is 802.1D.RSTP is Rapid Spanning-Tree Protocol defined by the 802.1w IEEE standard.MSTP is Multiple Spanning-Tree Protocol defined by the 802.1s IEEEstandard.PVST is Per VLAN Spanning-tree proprietary implementation of STP on CiscoequipmentPVST+ is the implementation of PVST on 802.1q links.
Spanning-Tree on HP ProCurve Switches
802.1D and 802.1w (RSTP)All HP ProCurve switches implement both of these STP standards. On HP ProCurve, Spanning-Tree has to be activated, the default mode is then Rapid STP.
MSTP 802.1sIt is supported on most manageable switches except 2500 and 4100 switchesPlease refer to switch documentation.
Spanning-Tree on Cisco Switches
PVST+By default, Cisco switches run PVST+. PVST is the implementation of STP onISL links (Cisco proprietary multi-VLAN encapsulation) while PVST+ runs on 802.1q links .
In PVST+, there is one instance of STP per VLAN and BPDUs use a proprietary Multicast Mac Address. They are not “understood” by HP ProCurve switches (except by ProCurve 9300M and 9400M) and are then flooded as a regular multicast. So, regarding PVST+ BPDUs, HP ProCurveswitches appear as a hub. However, Native VLAN (untagged VLAN of a tagged link equal to VLAN 1 bedefault) is an exception. In Native VLAN, the Cisco switches send standardSTP BPDUs, which are “understood” by HP ProCurve switches. This is how both platform interact.
Cisco has also introduced Rapid PVST+, a PVST+ implementation thatintegrates Rapid STP principles.
Prestandard MSTPMSTP should not be confused with the prestandard version of MSTP.
MSTP (802.1s)You must run the latest versions of IOS to get support of MSTP (check onCisco web site).
CautionSupport for the IEEE 802.1s standard has been introduced around September 2005 by Cisco in the IOS. One should refer to Cisco web site for IOS supportof compliant MSTP (*). Caution should be taken on not confusing theprestandard MST and the compliant IEEE 802.1s MST. If configuration ofboth modes looks exactly the same, the prestandard does NOTinteroperate with the MSTP on ProCurve as this one complies with IEEE 802.1s standard.
(*) Versions of IOS implementing the Compliant IEEE 802.1s starts with:12.2(18) for Catalyst 6500, 12.2(25)SG for Catalyst 4500 and 12.2(25)SECon Catalyst 35xx, 37xx, and 2970.
What Spanning-Tree mode should you choose between Cisco and ProCurve Switches?
MSTP is obviously the ideal choice because it is standard based andsupported by both vendors, it converges quickly and allows load-balancing oftraffic on uplinks with appropriate configuration.
If not all your devices support MSTP yet, a progressive migration to MSTP can be put in place as it interoperates with Standard, Rapid Spanning Treemodes and with PVST via the Native Vlan.
Note that all STP modes interoperate via the standard spanning-tree modealso named the Common Spanning-Tree (CST). So whatever is your choice,you should always carefully define the root and secondary root of the CST. On Cisco look after priority of STP in the Native Vlan (vlan 1 bydefault), on ProCurve look after the “global” priority of STP.
MSTP Configuration
Procurve-Edge-1
The parameters for the MSTP domain has been defined as followed:Configuration Name = procurve-cisco (case sensitive)Configuration Number = 1Instance 1 = vlans 1, 10, 20Instance 2 = vlans 30, 40
For load balancing of traffic among links, Cisco-core-1 is defined as Root of instance 0 and 1 (priority 0) and secondary root of instance 2 (priority 4096)
Uplinks are defined as 802.1q links. They are named “trunks” in Ciscoterminology and “tagged links” in ProCurve terminology. The “nonegogiate”feature means that we do no use the Dynamic Trunk Protocol to negotiatethe status of the uplink.
Access ports (Cisco Terminology) or Edge ports (ProCurve terminology) aredefined as untagged members of a Vlan. The portfast mode defines them as Edge port in Spanning tree terminology.
The Virtual IP used as Default Gateway for the various VLANs are set usingHSRP (Hot Standby Router Protocol), the Cisco proprietary protocol.As Cisco-Core-1 is the Root of MST instance 1, we also set it as Master of theVirtual IP of Vlans 1, 10 & 20. And as it is secondary root for MST instance 2, we define it as the Backup of Virtual IP in Vlans 30 & 40.
For load balancing of traffic among uplinks, Cisco-core-2 is defined as Root ofinstance 2 (priority 0) and secondary root of instance 0 and 1 (priority 4096)
Because Cisco-Core-2 is set as the secondary Root of MST instance 1, wedefine it as HSRP backup of the Virtual IP of VLANs 1, 10 & 20.And because it is root of MST instance 2, we set it as the Master of Virtual IPin VLANs 30 & 40.
interface Vlan1 ip address 10.1.1.2 255.255.255.0 standby 1 ip 10.1.1.254 standby 1 timers 1 3 !interface Vlan10 ip address 10.1.10.2 255.255.255.0 standby 10 ip 10.1.10.254 standby 10 timers 1 3 !interface Vlan20 ip address 10.1.20.2 255.255.255.0 standby 20 ip 10.1.20.254 standby 20 timers 1 3 !interface Vlan30 ip address 10.1.30.2 255.255.255.0 standby 30 ip 10.1.30.254 standby 30 timers 1 3 standby 30 priority 255
Uplinks ports are 1 and 2vlan 1 name "DEFAULT_VLAN" untagged 1-24 ip address 10.1.1.3 255.255.255.0 exit vlan 10 name "VLAN10" untagged 11-15 tagged 1-2 no ip address exit vlan 20 name "VLAN20" untagged 16-20 tagged 1-2 no ip address exit vlan 30 name "VLAN30" untagged 21-25 tagged 1-2 no ip address exit vlan 40 name "VLAN40" untagged 25-30 tagged 1-2 no ip address exit
Let’s enable Spanning-tree. It default on MSTP on the latest ProCurveswitches: 3500yl, 5400zl and 4200vl
spanning-tree
Default port configuration in MSTP is non Edge and Point-to-Point. We defineEdge ports as “Edge”.
spanning-tree 11-30 edge-port
MSTP Configuration: Name, Revision and instances match the one of otherswitches in MSTP domain
Configuration is similar to the configuration of ProCurve-Edge-1.In our example ProCurve-Edge-2 is a 3400. Spanning-tree mode defaults to RSTP. And we have to turn it on MSTP mode that requires a reboot.
hostname "ProCurve-Edge-2" max-vlans 16
vlan 1 name "DEFAULT_VLAN" untagged 1-9,18-24 ip address 10.1.1.4 255.255.255.0 no untagged 10-17 exit vlan 10 name "VLAN10" untagged 10-11 tagged 1-2 exit vlan 20 name "VLAN20" untagged 12-13 no ip address tagged 1-2 exit vlan 30 name "VLAN30" untagged 14-15 no ip address tagged 1-2 exit vlan 40 name "VLAN40" untagged 16-17 no ip address tagged 1-2 exit
In the following displays: note that theMac Address of Cisco Core-1 is 0010.0db1.7100 or 00100d-b17100Mac Address of Cisco Core-2 is 0010.0db3.1200 or 00100d-b31200
On Cisco-Core-1 The following command displays the parameters of MSTP configuration.Note that Cisco shows all the non assigned VLANs in Instance 0 (=ISTInstance) where ProCurve shows the non assigned AND created Vlans only.
Status of MSTP spanning tree in each instance. Cisco-Core-1(0010.0db1.7100 ) is root in instances 0 and 1. Cisco-Core-2(0010.0db1.7100) is root in instance 2.
Core-Cisco-1#show spanning-tree mst
##### MST0 vlans mapped: 2-9,11-19,21-29,31-39,41-4094 Bridge address 0010.0db1.7100 priority 0 (0 sysid 0) Root this switch for the CIST Operational hello time 2 , forward delay 15, max age 20, txholdcount 6 Configured hello time 2 , forward delay 15, max age 20, max hops 20
Status of MSTP spanning tree in each instance.Cisco-Core-1 (0010.0db1.7100 ) is root in instances 0 and 1.Cisco-Core-2 (0010.0db3.1200) is root in instance 2.
Core-Cisco-2#show spanning-tree mst
##### MST0 vlans mapped: 2-9,11-19,21-29,31-39,41-4094 Bridge address 0010.0db3.1200 priority 4096 (4096 sysid 0) Root address 0010.0db1.7100 priority 0 (0 sysid 0) port Gi1/3 path cost 0 Regional Root address 0010.0db1.7100 priority 0 (0 sysid 0) internal cost 20000 rem hops 19 Operational hello time 2 , forward delay 15, max age 20, txholdcount 6 Configured hello time 2 , forward delay 15, max age 20, max hops 20
On ProCurve-Edge-1 Parameters of MSTP configuration. Note that display shows IST instance without any Vlans. In fact the vlans,including those not yet created, that are not associated with an existing instance are mapped to the IST instance.
ProCurve-Edge-1# show spanning-tree mst-config
MST Configuration Identifier Information
MST Configuration Name : procurve-cisco MST Configuration Revision : 1
Instance ID Mapped VLANs ----------- --------------------------------------------------- 1 1,10,20 2 30,40
The following display shows ports configuration.Note that uplinks are set as Non edge and others are set as Edge.
ProCurve-Edge-1# show spanning-tree 1-5 config
Multiple Spanning Tree (MST) Configuration Information
STP Enabled [No] : Yes Force Version [MSTP-operation] : MSTP-operation Default Path Costs [802.1t] : 802.1t MST Configuration Name : procurve-cisco MST Configuration Revision : 1 Switch Priority : 32768 Forward Delay [15] : 15 Hello Time [2] : 2 Max Age [20] : 20 Max Hops [20] : 20
| Prio BPDU Port Type | Cost rity Edge Pnt-to-Pnt MCheck Hello Time Filter ---- --------- + --------- ----- ---- ----------- ------ ------ 1 100/1000T | Auto 128 No Force-True Yes Use Global No 2 100/1000T | Auto 128 No Force-True Yes Use Global No 3 100/1000T | Auto 128 No Force-True Yes Use Global No 4 100/1000T | Auto 128 Yes Force-True Yes Use Global No 5 100/1000T | Auto 128 Yes Force-True Yes Use Global No
Status in IST Instance: Root port is 1 and alternate (blocked) is 2
ProCurve-Edge-1# show spanning-tree 1-2 instance ist
IST Instance Information
Instance ID : 0 Mapped VLANs :
Switch Priority : 32768
Topology Change Count : 4 Time Since Last Change : 11 mins
Regional Root MAC Address : 00100d-b17100 Regional Root Priority : 0 Regional Root Path Cost : 20000 Regional Root Port : 1 Remaining Hops : 19 Designated Port Type Cost Priority Role State Bridge ---- --------- --------- -------- ---------- ---------- ------------- 1 100/1000T 20000 128 Root Forwarding 00100d-b17100 2 100/1000T 20000 128 Alternate Blocking 00100d-b31200
Status in Instance 1: Root port is 1 and alternate (blocked) is 2
ProCurve-Edge-1# show spanning-tree 1-2 instance 1
MST Instance Information
Instance ID : 1 Mapped VLANs : 1,10,20
Switch Priority : 32768
Topology Change Count : 2 Time Since Last Change : 13 mins
Regional Root MAC Address : 00100d-b17100 Regional Root Priority : 0 Regional Root Path Cost : 20000 Regional Root Port : 1 Remaining Hops : 19 Designated Port Type Cost Priority Role State Bridge ---- --------- --------- -------- ---------- ---------- ------------- 1 100/1000T 20000 128 Root Forwarding 00100d-b17100 2 100/1000T 20000 128 Alternate Blocking 00100d-b31200
Status in Instance 2: Root port is 2 and alternate (blocked) is 1
ProCurve-Edge-1# show spanning-tree 1-2 instance 2
MST Instance Information
Instance ID : 2 Mapped VLANs : 30,40
Switch Priority : 32768
Topology Change Count : 4 Time Since Last Change : 13 mins
Regional Root MAC Address : 00100d-b31200 Regional Root Priority : 0 Regional Root Path Cost : 20000 Regional Root Port : 2 Remaining Hops : 19 Designated Port Type Cost Priority Role State Bridge ---- --------- --------- -------- ---------- ---------- ------------- 1 100/1000T 20000 128 Alternate Blocking 00100d-b17100 2 100/1000T 20000 128 Root Forwarding 00100d-b31200
ProCurve-Edge-1# show spanning-tree 1-2
Multiple Spanning Tree (MST) Information
STP Enabled : Yes Force Version : MSTP-operation IST Mapped VLANs :
Filtered Ports : Switch MAC Address : 001635-b487c0 Switch Priority : 32768 Max Age : 20 Max Hops : 20 Forward Delay : 15
Topology Change Count : 10 Time Since Last Change : 53 secs
IST Regional Root MAC Address : 00100d-b31200 IST Regional Root Priority : 4096 IST Regional Root Path Cost : 20000 IST Remaining Hops : 19
| Prio | Designated Hello Port Type | Cost rity State | Bridge Time PtP Edge ---- --------- + --------- ----- ---------- + ------------- ----- --- 1 100/1000T | 20000 128 Blocking | 001635-b487c0 2 Yes No 2 100/1000T | 20000 128 Forwarding | 00100d-b31200 2 Yes No
IP and HSRP Status Displays are shown to explain
Core-Cisco-1#show ip int brief Interface IP-Address OK? Method Status Protocol Vlan1 10.1.1.1 YES manual up up Vlan10 10.1.10.1 YES manual up up Vlan20 10.1.20.1 YES manual up up Vlan30 10.1.30.1 YES manual up up Vlan40 10.1.40.1 YES manual up up
Core-Cisco-1#sh standby brief P indicates configured to preempt. | Interface Grp Prio P State Active Standby Virtual IP Vl1 1 255 P Active local 10.1.1.2 10.1.1.254 Vl10 10 255 P Active local 10.1.10.2 10.1.10.254 Vl20 20 255 P Active local 10.1.20.2 10.1.20.254 Vl30 30 100 Standby 10.1.30.2 local 10.1.30.254 Vl40 40 100 Standby 10.1.40.2 local 10.1.40.254
Core-Cisco-2#show ip int brief Interface IP-Address OK? Method Status Protocol Vlan1 10.1.1.2 YES manual up up Vlan10 10.1.10.2 YES manual up up Vlan20 10.1.20.2 YES manual up up Vlan30 10.1.30.2 YES manual up up Vlan40 10.1.40.2 YES manual up up
Core-Cisco-2#sh standby brief P indicates configured to preempt. | Interface Grp Prio P State Active Standby Virtual IP Vl1 1 100 Standby 10.1.1.1 local 10.1.1.254 Vl10 10 100 Standby 10.1.10.1 local 10.1.10.254 Vl20 20 100 Standby 10.1.20.1 local 10.1.20.254 Vl30 30 255 P Active local 10.1.30.1 10.1.30.254 Vl40 40 255 P Active local 10.1.40.1 10.1.40.254
Cisco as Core running PVST+, HP ProCurve as Edge running RSTP
Procurve-Edge-1
Cisco-2Cisco-1
Uplinks are tagged with VLANs 10,20, 30 & 40 Untagged in Vlan 1 (Native-Vlan)
In this topology, uplinks are tagged with VLANs 10, 20, 30 and 40 anduntagged for VLAN 1. On Cisco, it is named the Native VLAN. In PVST+ Cisco-1 is the primary Root for VLANs 1, 10 and 20 and Cisco-2 the secondary Root. Cisco-2 is the primary Root for VLANs 30 and 40 and Cisco-1 the secondaryRoot.ProCurve-Edge-1 is an access switch.
Cisco-1 PVST+ Configuration
Following define PVST+ Spanning-Tree mode, allows PVST+ to run for VLANsabove 1023 an up to 4095.
Conf t hostname Cisco-1 Spanning-Tree mode pvstSpanning-Tree extend system-id
Cisco-1 is the primary Root for VLAN 1, 10, 20 and the secondary Root for VLAN 30,40
Although it is not mandatory, the STP timers have been lowered to speedconvergence time. One should pay attention in using those values as it maycreate instability if not applied properly. The following values are acceptablein a network with a “diameter” of 3, which means that BPDUs will not crossmore than 3 switches before returning to originator Root switch.
Enable PortFast on all ports except the Cisco “trunk” ports
Spanning-Tree portfast default
ProCurve Edge-1 configuration
ProCurve Edge-1 is an Edge/Access switch.
Confhostname "ProCurve-Edge-1"
STP configuration. Default mode is RSTP.In RSTP mode, default configuration of all ports is Point-to-Point and Edge(fast convergence). To follow the specifications of the standard, the Uplinksare defined as Point-to-Point and Non Edge.
no Spanning-Tree A15-A16 edge-port
The following enables Spanning-Tree.
Spanning-Tree
Default mode is RSTP (802.1w), other modes are Standard STP (802.1D) andMSTP (802.1s). Changing mode requires a reboot.
In the following displays, Mac address of Cisco-1 is 0013.c382.a900 and Macaddress of Cisco-2 is 0013.c392.d200.
PVST+ status on Cisco-1.
Display confirms Cisco-1 as the primary Root for VLANs 1, 10, 20 and secondary Root for VLANs 30 and 40 and all ports are in forwarding mode.
Cisco-1#sh Spanning-Tree
VLAN0001 Spanning-Tree enabled protocol ieee Root ID Priority 1 Address 0013.c382.a900 (Cisco-1) This bridge is the root Hello Time 1 sec Max Age 6 sec Forward Delay 4 sec
Bridge ID Priority 1 (priority 0 sys-id-ext 1) Address 0013.c382.a900 Hello Time 1 sec Max Age 6 sec Forward Delay 4 sec Aging Time 300
VLAN0010 Spanning-Tree enabled protocol ieee Root ID Priority 10 Address 0013.c382.a900 (Cisco-1) This bridge is the root Hello Time 1 sec Max Age 6 sec Forward Delay 4 sec
Bridge ID Priority 10 (priority 0 sys-id-ext 10) Address 0013.c382.a900 Hello Time 1 sec Max Age 6 sec Forward Delay 4 sec Aging Time 300
The Spanning-Tree timers defined in VLAN 1 dictate convergence time. Withdefault timers (Hello=2 sec, Forward Delay= 15 sec, Max-age=20 sec),convergence time is between 30 and 50 sec. With the values that we applied(Hello=1 sec, Forward Delay= 4 sec, Max-age=6 sec), convergence timenever exceeded 8 sec.
Conclusion
See figure for resulting STP topology.If Cores of L2 networks are Cisco switches, one should take care of configuration of PVST+ in VLAN 1 (Native VLAN) as that will dictate theresulting topology. STP Timers in Native-VLAN will drive convergence time
What about Cisco Rapid PVST?
The same test has been run implementing the Rapid PVST mode on the Ciscocores.Regarding finale topology, same results have been obtained. However no significant improvement in speed convergence has resulted.In other words, HP ProCurve RSTP and Cisco Rapid PVST interacts in Vlan 1 as RSTP or standard STP interacts with PVST, but Rapid STP mechanisms arenot functioning.
In its Rapid PVST mode implementation, Cisco does not use the standardcosts of Rapid STP but rather the cost of standard STP. For example FastEthernet cost is 19 and not 200000.
HP ProCurve as Core running RSTP, Cisco as Edge running PVST+
Sample topology
In this topology, uplinks are tagged for VLANs 10, 20, 30 and 40 and untagged for VLAN 1.ProCurve-Core-1 and 2 are defined as Root and secondary Root of RSTP.Cisco-1 and Cisco-2 use standard PVST+ configuration.
In the following, only the Spanning-Tree Configuration is shown.
Configuration of RSTP on ProCurve-Core-1 and 2
Confhostname "ProCurve-Core-1/2"
Uplink ports are defined as Non Edge. Default is Edge and Point-to-Point.
no Spanning-Tree A14-A16 edge-port
ProCurve-Core-1 is the Root (priority 0) of the STP and ProCurve-Core-2 thesecondary Root (priority 1).
Spanning-Tree priority 0
STP timers are lowered to speed convergence time. Values are acceptable for a network where access switches are connecteddirectly to the core switches or are in a stack connected directly to the cores.
ProCurve-Core-1 is seen, as expected, as the Root switch. Note that uplinks A15 and A16 are in blocking state, i.e. they’re not thedesignated port of their segment.The first criterion to elect the Designated port of a segment is the path-costof switch to the Root. In this case the Root path-cost of access switches
Cisco-1 and 2 (value 4) is lower than the Root path-cost of ProCurve-Edge-2(value 20000).Cisco switches use standard STP values (4 for Gigabit, 19 for Fast Ethernet)and HP ProCurve switches use Rapid STP values (20000 For Gigabit, 200000for Fast Ethernet).
ProCurve-Core-2# sh span a14-a16
Rapid Spanning-Tree (RSTP) Information
STP Enabled : Yes Force Version : RSTP-operation
Switch Priority : 4096 Hello Time : 1 Max Age : 6 Forward Delay : 4
Topology Change Count : 108 Time Since Last Change : 23 secs
Root MAC Address : 000e7f-060100 (ProCurve-Core-1) Root Path Cost : 20000 Root Port : A14 Root Priority : 0
STP status in VLAN 10, 20, 30 and 40 of Cisco-1 and 2
In VLANs 10, 20, 30 and 40, ProCurve-Core-1 and 2 forward Cisco PVSTBPDUs as any other frames. They are “transparent” to the Cisco switches.Cisco-1 is the Root switch because of its Mac address.
Cisco-1#sh Spanning-Tree vlan 10 VLAN0010 Spanning-Tree enabled protocol ieee Root ID Priority 32778 Address 0013.c382.a900 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32778 (priority 32768 sys-id-ext 10) Address 0013.c382.a900 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300
In VLAN 10, 20, 30 and 40, Status is the same as before
Cisco-1#sh span vlan 10
VLAN0010Spanning-Tree enabled protocol ieee Root ID Priority 32778 Cost 4 Address 0013.c382.a900 (cisco-1) This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32778 (priority 32768 sys-id-ext 10) Address 0013.c382.a900 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300
Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- ------------------------ Gi1/0/1 Desg FWD 4 128.3 P2p Peer(STP)Gi1/0/2 Back BLK 4 128.4 P2p Peer(STP)
On Cisco-2
Cisco-2#sh span
VLAN0001 Spanning-Tree enabled protocol ieee Root ID Priority 0 Address 000e.7f06.0100 Cost 4 Port 3 (GigabitEthernet1/0/1) Hello Time 1 sec Max Age 6 sec Forward Delay 4 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1) Address 0013.c392.d200 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300