Cisco ASR 903 Guide

Layer 2 Solution
REP ▀
Cisco ASR 903 Router Design and Deployment Guide▄
OL-30526-01
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REP
The Resilient Ethernet Protocol (REP) is a Cisco proprietary protocol that provides an alternative to the Spanning
Tree Protocol (STP). REP provides a way to control network loops, handle link failures, and improve convergence
time. It controls a group of ports connected in a segment, ensures that the segment does not create any bridging
loops, and responds to link failures within the segment. With REP at least one port is always blocked in any given
segment, that is, the alternate port. The blocked port helps ensure that the traffic within the segment is loop-free by
requiring traffic flow to exit only one of the edge ports, and not both. REP provides a basis for constructing
complex networks and supports VLAN load balancing.
Figure 6. REP
ASR903-R2
Gi 0/2/1
Gi 0/2/0
Gi 0/2/0
Gi 0/2/1 Gi 0/2/1
Gi 0/2/0
Gi 0/2/0
Gi 0/2/1
ASR903-R1
ASR903-R4
ASR903-R3
ASR903-R1 Configuration
interface GigabitEthernet0/2/0
no ip address
negotiation auto
rep segment 1 edge primary
rep stcn stp
rep block port preferred vlan 1-4094
service instance trunk 1 ethernet
encapsulation dot1q 1-4094
rewrite ingress tag pop 1 symmetric

Cisco ASR 903 Specifications

General

Brand	Cisco
Model	ASR 903
Category	Network Router
Language	English