[cisco-voip] Server-groups and failover...

[Pawlowski, Adam]

Sure

Again some time ago but what we’d run into was that PSTN calls in would fail on the network side if we didn’t signal progress back within a period of time. With stock timers, it never was able to move through all of the available call processors (4) before this happened, so you’d not really had effective redundancy, nor could it fall through for handling if you wanted to do that. It was based on watching the debugging to see how the flow went when we ACL’d off various UCMs from the CUBE itself.

As you can see form other postings in the thread, I did not know enough about this at the time to adjust other timers to account for either mid-call or call teardown signaling. I’m still learning, as always.

On the outbound end to the ITSP we also had a BGP relationship setup with them to tear down routing if the physical circuit failed somewhere outbound. That allowed us two disparate CUBEs that would still be available for call routing, resources, etc even if we lost an outbound circuit – we could still reach both peers for LB/HA across the surviving one at another structure from either CUBE in the arrangement.

Adam



From: Anthony Holloway <avholloway+cisco-voip at gmail.com>
Sent: Tuesday, November 19, 2019 9:37 AM
To: Pawlowski, Adam <ajp26 at buffalo.edu>
Cc: Jonathan Charles <jonvoip at gmail.com>; Cisco VoIP Group <cisco-voip at puck.nether.net>
Subject: Re: [cisco-voip] Server-groups and failover...

I'm curious as to how you arrived at those settings. Would you be able to share your path to arriving at those specific settings?

I typically leave the 500ms alone but do lower the retries to so that the total worst case delay would be ~3sec. For no other reason than that was always the for h323 tcp timeout we all used to use.

I do also use OPTIONS though, because in my opinion, tweaking/enabling both provides the best user experience. Though I don't typically adjust the default OPTIONS timers and retries. Do you?

On Tue, Nov 19, 2019, 7:06 AM Pawlowski, Adam <ajp26 at buffalo.edu<mailto:ajp26 at buffalo.edu>> wrote:
I think I had to make some adjustments to our timers as well to get this to work before network timeout or similar:

sip-ua
retry invite 2
timers trying 100
!

I know I also goofed this up between dial peer group and server group, one of the two will retry within the group, the other sure doesn’t.


From: cisco-voip <cisco-voip-bounces at puck.nether.net<mailto:cisco-voip-bounces at puck.nether.net>> On Behalf Of Jonathan Charles
Sent: Monday, November 18, 2019 11:56 PM
To: Anthony Holloway <avholloway+cisco-voip at gmail.com<mailto:avholloway%2Bcisco-voip at gmail.com>>
Cc: cisco-voip at puck.nether.net<mailto:cisco-voip at puck.nether.net>
Subject: Re: [cisco-voip] Server-groups and failover...

I pasted the wrong part of the script (to manually change it)...

Here is the actual config:



voice class server-group 1
 ipv4 172.31.120.43
 ipv4 172.31.125.43 preference 2
 description Verizon SIP
!

Jonathan

On Mon, Nov 18, 2019 at 10:22 PM Anthony Holloway <avholloway+cisco-voip at gmail.com<mailto:avholloway%2Bcisco-voip at gmail.com>> wrote:
First off, I'm wondering why it says "no ipv4" in front of your two addresses.  That might be your problem right there.

Secondly, I'd recommend putting an explicit preference on your entries, it's just better for everyone, and you don't get a credit back from Cisco for saving on a few ascii characters by implicitly using the default.  Plus, if the default is 0, which it is, then your next preference should be technically 1.  But then having nothing and 1 seems silly, because if pref 1 is actually pref 2, then well, might as well call them pref nothing and pref 8.  I digress.

You might not have failed over, because you might not have provided the system with the correction conditions to failover...E.g., you didn't wait long enough.

No seriously, by default SIP failover occurs after 30 seconds.  Unless, did you lower the retry count under sip-ua?  Or did you enable SIP options?  If you enabled SIP options, have your confirmed that it's turned on correctly?

Can you share the output of the following commands:

show run | section sip-ua|sip.options-keepalive

show dial-peer voice summary

Feel free to redact what you need to, in terms of IPs or usernames/passwords.  I am only looking for the features and settings for retries and keepalives.


On Mon, Nov 18, 2019 at 9:26 PM Jonathan Charles <jonvoip at gmail.com<mailto:jonvoip at gmail.com>> wrote:
Using session server groups on outbound dial-peers and it does not appear to be failing over:


voice class server-group 1
 no ipv4 172.31.125.43  preference 2
 no ipv4 172.31.120.43
 description Verizon SIP
!

We had the 172.31.20.43 go down (no response to invites) and we did NOT failover to the second (.125.43)...

What is needed to force a failover to the next configured SBC?


Jonathan
_______________________________________________
cisco-voip mailing list
cisco-voip at puck.nether.net<mailto:cisco-voip at puck.nether.net>
https://puck.nether.net/mailman/listinfo/cisco-voip
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20191119/8af0d5e7/attachment.htm>