Cisco ASR 903 Guide

Layer 2 Solution
Spanning-Tree Configuration ▀
Cisco ASR 903 Router Design and Deployment Guide▄
OL-30526-01
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Figure 3. Spanning Tree
ASR903-PE2
Gi0/1/2 Gi0/1/2
Gi0/1/0 Gi0/1/2Gi0/1/0Gi0/1/1
ASR903-PE1ASR903-CE1
Customer A
Site 1
ASR903-CE2
172.16.11.0/24 - SubnetB
172.16.11.0/24 – SubnetB
Customer A
Site 2
10 10 10
40 11
10 10
11 40 11
30
11 11 11
172.16.10.0/24 - SubnetA
172.16.10.0/24 – SubnetA
10 30
Gi0/1/1 Gi0/1/1
x
ASR903-PE1 and ASR903-PE2 Configuration
spanning-tree mode mst ! enable MST on the ASR903
interface GigabitEthernet0/1/1
no ip address
negotiation auto
service instance trunk 1 ethernet
encapsulation dot1q 30-40
rewrite ingress tag pop 1 symmetric
bridge-domain from-encapsulation
!
service instance 2 ethernet
encapsulation untagged ! enable l2protocol peering
l2protocol peer
bridge-domain 1
interface GigabitEthernet0/1/2
no ip address
negotiation auto
service instance trunk 1 ethernet
encapsulation dot1q 30-40
rewrite ingress tag pop 1 symmetric
bridge-domain from-encapsulation
!
service instance 2 ethernet
encapsulation untagged
l2protocol peer ! enable l2protocol peering
bridge-domain 1
Verify Spanning-tree Configuration
ASR903-PE1# show span vlan 30
MST0
Spanning tree enabled protocol mstp
Root ID Priority 32768
Address 7010.5c51.8fbb

Cisco ASR 903 Specifications

General

Brand	Cisco
Model	ASR 903
Category	Network Router
Language	English