REP(Resilient Ethernet Protocol) Topology Issue

[himanshudwivedi]

Hello Senior's,

I am about to configure RESILIENT ETHERNET PROTOCOL, on my live environment and my topology is as below.

As per customer requirements, between SW1, SW2 and SW3 normal spanning tree is working. And between SW2, SW3, SW4 and SW5 I want to run REP(resilient Ethernet protocol), show will REP work fine in this case.... If yes.... What configuration should I do on switches for REP...

If I configure Edge Port on SW2(Te1/0/2) and SW3(Te1/0/2) using rep segment 1 edge, and add both the ports of of SW4 and SW5 by using rep segment 1. What will be the impact or topology will work fine.

[Georg Pauwen]

Hello,

the short answer is: your planned topology is by the book. You will have what is called a REP Open Segment.

Check page 3 Figure 1 of the attached doument:

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/lanswitch/configuration/xe-3s/lanswitch-xe-3s-book/lsw-cfg-rep.pdf

[himanshudwivedi]

I have configured the same as per Open segment topology, it is showing Alternate Port on SW5 (Ten1/0/1), but as I disconnect cable between SW1 and SW3, Alternate port still remains alternate and SW3 become totally isolated.. How to face such situations.

[Georg Pauwen]

Hello,

what does spanning tree do when you disconnect the link ?

[himanshudwivedi]

As I disconnect cable between SW1 and SW3, and execute command show spanning-tree, it says that spanning-tree does not exists.

[Georg Pauwen]

Hello,

make sure you have:

rep stcn stp

configured on the edge ports. Actually it might be a good idea to post the full configs of Switch1 and Switch3.

[himanshudwivedi]

Running config are attached of SW1, 2 and 3...... for other switches I have simply executed rep segment 1 command on interface...

I will try Running rep stcn stp command.. .. What will be the impact of this command ???? 

If there is break in cable between SW1 and SW3, will the rep segment ALT port become open and start forwarding traffic???