[cisco-voip] SIP Fail over

[NateCCIE]

When you say level3 does not support options ping, do you mean they won't
ping you for failover, or they don't allow you to send it to them?  Only two
messages and the lack of any response will busy the endpoint, anything else
if good enough for CUBE.

 



 

From: cisco-voip <cisco-voip-bounces at puck.nether.net> On Behalf Of Ryan Huff
Sent: Thursday, December 20, 2018 10:35 AM
To: Erik Anderson <erik.anderson.85 at gmail.com>; cisco-voip voyp list
<cisco-voip at puck.nether.net>
Subject: Re: [cisco-voip] SIP Fail over

 

Couldn't you just use voice class sip options/keepalives to mark when the
ITSP is down, so CUCM marks the trunk out of service and fails to the next
route group member immediately (ideally, your secondary CUBE)? Seems like
thats a more natural way of doing it versus using IP SLAs...

 

Thanks,

 

- Ryan

  _____  

From: cisco-voip <cisco-voip-bounces at puck.nether.net
<mailto:cisco-voip-bounces at puck.nether.net> > on behalf of Erik Anderson
<erik.anderson.85 at gmail.com <mailto:erik.anderson.85 at gmail.com> >
Sent: Thursday, December 20, 2018 12:03 PM
To: cisco-voip voyp list
Subject: [cisco-voip] SIP Fail over 

 

Morning Folks, 




We have implemented a new SIP solution with Level 3 and found that we have
outbound calling failover issues. When a CUBE loses its ability to talk to
its Level 3 Peer, but can still talk to CUCM outbound calls will still
connect to the CUBE, but fail connecting to Level 3. In turn CUCM still
thinks the call is connected since the CUCM SIP trunk remains up to the
CUBE.

 

Architecture Notes:

 

4 Locations with 1 CUBE Each

4 CUCM SIP Trunks with each connecting to one of the 4 CUBEs

4 CUCM Route Groups with Various CUBE/SIP Trunks assigned a Distribution
Algorithm of Top Down

Each CUBE has 2 SIP Peers

Each CUBE can only talk to its respective SIP peer via its local Level 3
Transport to reduce call control latency by not allowing it to use the DMVPN
backup network

Level 3 does not support SIP Options Ping

CUCM Trunks have SIP Options Ping enabled

 

Call Flows:

 

Working Flow:

 

Phone ----> SLRG ----> Route Group Member #1 ----> CUBE SIP TRUNK ----> CUBE
----> Level 3 Transport ----> Level 3 SIP Peer #1/#2 ----> Call Completes

 

 

CUBE Failure:

 

Phone ----> SLRG ---->

         Route Group Member #1 ----> CUBE SIP TRUNK --X--> CUBE (CUCM Cant
Reach CUBE)

 

        CUCM Routes Call to Next Route Group Member

 

                              Route Group Member #2 ----> CUBE SIP TRUNK
----> CUBE ----> Level 3 Transport ----> Level 3 SIP Peer #1/#2 ----> Call
Completes

 

Level 3 Transport Failure/SIP Server Failure:

 

Phone ----> SLRG ---->

         Route Group Member #1 ----> CUBE SIP TRUNK ----> CUBE --X--> Level
3 Transport (CUBE Cant Reach Level 3 SIP Server)

 

        CUCM Thinks Call Connects since the CUBE accepts the call, Phone
gets dead air, never tries the next RG Member

 

 

My idea to fix this is to use an IPSLA to ping the pingable address on the
Level 3 SIP Servers. If both address are unreachable then shutdown the CUCM
Dial-Peers. This doesn't sounds like the best way of fixing it, but it
should work. 

 

If any has any other better ideas please let me know.

-- 

Erik Anderson

Telecom Manager

Some Random Corp.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20181220/f1340a0b/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.png
Type: image/png
Size: 25345 bytes
Desc: not available
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20181220/f1340a0b/attachment.png>