REP with HSRP

[XWL]

Hello all Network Guru,

I have set up the REP ring for 2 Redundant IE5000 industrial switches and 3 Access switches.

these two IE5000 switches have been configured as HSRP.

for the REP ring:

two ports in 1st IE5000 have been configured as Primary Edge Port and Edge Port.

two ports in 2nd IE5000 and rest of access switches have been configured as Transit ports.

I have tested and the network convergence time to drop SW01 and drop SW02 are almost the same ( 0 or 1 ping lost).

the testing is pinging from VLAN 10 in Access switch SW-A to Servers in VLAN 100. The result is promising and looks all good.

However, I still have doubt whether it is the best setup. 

I understand that the best solution is to stack up these two  IE5000 switches. see the link for details.

can anybody point out any potential issue for my setup?

Thank you.

[Georg Pauwen]

Hello,

as I understand it, horizontal stacking is mainly used to connect (via the 10G ports) IE switches that are physically far apart. Is this your situation ? Otherwise, your REP/HSRP configuration looks by the book (as outlined in the document attached)...

High-Availability Seamless Redundancy in
the Factory Network

https://www.cisco.com/c/en/us/td/docs/solutions/Verticals/Machines/HSR/ConnMach-HSR.pdf

[XWL]

Thanks, Georg

ironically, both Distribution switch SW01 and SW02 are in the same server and network panel.

Figure 7 in the file you mentioned on page 17 gave me the idea.

Why not configure the edge ports in other access switches instead in the distribution switches! The edge ports do not have to be in the distribution switch!

so the ports in SW01 and SW02 will be the transit ports,

the port Gi1/1 in SW-A will be the primary edge port and

the port Gi1/1 in SW-C will be the (secondary) edge port.

see the revised architecture. I highlighted what has been changed in the yellow box.

[BrianSekleckiGE]

It is interesting that you chose to use REP Ring connection between your two HSRP Layer3 agg/core switches, and not A dot1Q Trunk (Port Channel, etc.) running STP ?

Its been two years; how your setup functioning?

[XWL]

Hi
REP ring has the following advantages

1. It is ring obviously
2. The network convergence is better than EtherChannel. REP can be 50-150ms, while EtherChannel is around sub 250ms.

Refer to attached screen shot I found somewhere.

[cid:image001.jpg@01D65798.FC3B2B70]

[BrianSekleckiGE]

@XWL 

 I had time this weekend to enumerate some of the potential problems with having HSRP members inter-connected with REP.

 The problem that vex's me the greatest:

 What happens if the Ring's topology changes; REP doesn't let you force-reconcile the ALT/Alternate port (blocked) .

  That means your REP segment link between HSRP could become the ALT port.

   That means HSRP hello traffic could flow entirely around the ring.

 (Sorry about the hasty/sloppy nature of this diagram)

~BAS