[cisco-voip] SIP Fail over

[Anthony Holloway]

He did mention that L3 does not support OPTIONS.  But yes, OPTIONs is the
better solution.

On Thu, Dec 20, 2018 at 11:36 AM Ryan Huff <ryanhuff at outlook.com> wrote:

> 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> on behalf of Erik
> Anderson <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.
> _______________________________________________
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> cisco-voip at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-voip
>
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