[Spce-user] Contact header too long?

Andreas Granig agranig at sipwise.com
Fri Mar 24 09:27:44 EDT 2017


There is no limit in the SIP RFC (unless I overlooked something), and
different vendors handle it differently. E.g. the Dialogic SBC has a
limit at 1024, see

Actually not much you can do here. The ngcpct is there to work around
issues for other user-agents, which don't handle a Contact of
very well, which we used to send in certain scenarios (which is also
totally fine in theory, but in practice breaks some clients). Therefore
we put the IP of the kamailio-lb there and store the original one in
masked form in the ngcpct param and reconstruct it in other scenarios.


On 03/23/2017 07:47 PM, Marco Teixeira wrote:
> So... searching around the mailing list archives, I can see that in the
> ngcpct parameter was 22 chars shorter back in 2014...
> https://lists.sipwise.com/pipermail/spce-user/2014-January/005675.html
>  is this something I can manipulate? the length of ngcpct?
> =Marco
> On Thu, Mar 23, 2017 at 6:20 PM, Marco Teixeira <admin at marcoteixeira.com
> <mailto:admin at marcoteixeira.com>> wrote:
>     Forgot to mention, the peer is a Metaswitch Perimeta SBC.
>     =Marco
>     On Thu, Mar 23, 2017 at 6:04 PM, Marco Teixeira
>     <admin at marcoteixeira.com <mailto:admin at marcoteixeira.com>> wrote:
>         Hi list,
>         Trying to figure out a problem where calls incoming from peer
>         get dropped around 900 secs.
>         Peer vendor claiming the issue is, and I quote:
>         "(...) because the request-uri is >160 bytes. (...) The reason
>         the Request-URI is so long is due to the long contact header
>         coming from -
>         Contact: <sip:ngcp-lb at
>         <http://sip:ngcp-lb@>;ngcpct=7369703a3332372e302e302e313a353338303b707278726f7574653d33>" 
>         Please ask the customer to reduce the length of the ngcpct
>         parameter coming from their SIP server."
>         Has anyone ever came across this issue? 
>         Is 160 bytes limits even on the SIP RFC?
>         How can i shorten or stop using ngcpct parameter in contact?
>         Apreciate your help, 
>         Marco
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