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N4032, MLAG, MSTP, VRRP not synchornizing or pingable between peers, stuck on Master state
I've set up MLAG peer connection between two N4032s and to a few servers following this whitepaper - section 7: http://en.community.dell.com/techcenter/extras/m/white_papers/20438244/
Everything is up and running, except I'm having issues with VRRP. No matter what I try, this is the output I get on the switches, both get stuck on being the Master. Nevertheless, the VRRP IP is pingable from the servers.
ACCESS1#show vrrp
Admin Mode..................................... Enable
Router Checksum Errors......................... 0
Router Version Errors.......................... 0
Router VRID Errors............................. 0
Vlan 30 - Group 30
Primary IP Address............................. 10.32.3.1
VMAC Address................................... 0000.5E00.011E
Authentication Type............................ None
Priority....................................... 150
Configured Priority............................ 150
Advertisement Interval (secs).................. 1
Accept Mode.................................... Enable
Pre-empt Mode.................................. Enable
Pre-empt delay................................. 0
Administrative Mode............................ Enable
State.......................................... Master
Timers Learn mode.............................. Disable
Description....................................
ACCESS2>show vrrp
Admin Mode..................................... Enable
Router Checksum Errors......................... 0
Router Version Errors.......................... 0
Router VRID Errors............................. 0
Vlan 30 - Group 30
Primary IP Address............................. 10.32.3.1
VMAC Address................................... 0000.5E00.011E
Authentication Type............................ None
Priority....................................... 200
Configured Priority............................ 200
Advertisement Interval (secs).................. 1
Accept Mode.................................... Enable
Pre-empt Mode.................................. Enable
Pre-empt delay................................. 0
Administrative Mode............................ Enable
State.......................................... Master
Timers Learn mode.............................. Disable
Description....................................
I've been doing some trobleshooting and found a strange behavior. If I dissable the VRRP in one of the switches, I can still ping the VRRP IP (10.32.3.1) from the access servers located on vlan 30, but at the same time the peer switch is not able to ping the IP.
So my guess is that both switches get stuck on Master state as they can't pass VRRP messages trough the vpc-peer. Any ideas?
Here is the config for both switches
ACCESS1: https://pastebin.com/3b5tUhcm
ACCESS2: https://pastebin.com/UB85TWNg
Thanks!
Anonymous
274.2K Posts
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April 4th, 2018 12:00
The config looks ok to me. Perhaps the two switches are not able to communicate on VLAN 30 with one another. Do you have a brief networking topology you can share? I see a lot of the port channels are set to Trunk mode, perhaps specifying the addition of VLAN 30 for the core connection?
uleinad
7 Posts
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April 5th, 2018 00:00
I thought about the same regarding VLAN30 not communicating, so went trobuleshooting and my findiings are that VLAN30 between the switches is definetly working as I do can ping the SVI IP from each peer switch. Meaning, ACCESS1 can ping 10.3.3.4 and ACCESS2 can ping 10.3.3.3. So I guess that VLAN30 is communnicating between the switches, otherwise the ping won't go through right?
I've done different tests, doing different variations, being more specific with the VLAN30 tagging but same results.
I've attached the network topology so I can help you understand it. Will keep troubleshooting meanwhile, many thanks for all the help.
tbarhorst
2 Posts
0
April 10th, 2018 12:00
Did you ever discover the reason for both switches being masters? I need to program a similar topology and also wonder if somehow you could share your topology so that I could also see it?
Anonymous
274.2K Posts
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April 11th, 2018 05:00
We are still actively working on this one. As of now, it would seem that this may be expected behavior when using VRRP and MLAG features together. The idea being that both switches will store the virtual IP and MAC address, both switches will be master, and both switches will forward packets. I will be sure to post back as soon as I have more concrete information.
Anonymous
274.2K Posts
0
April 11th, 2018 12:00
Looks like the answer was here all along, we just had to look in the right place.The config guide actually details this behavior on page 1076: https://dell.to/2GcZwE3
"If VRRP is enabled on a VLAN that has an MLAG port as its member, both
VRRP routers become VRRP masters operationally in the VLAN. This is to
allow load balancing of the northbound layer-3 traffic on the MLAG."