SIP Forking

[Anonymous]

Trying to implement a hosted PBX solution using a Genband C15 softswitch and Polycom VVX400 phones.  At the customer premise, we are planning to use a NetVanta 3140 as the  SIP and data router, and a NetVanta 1531P as the PoE switch.

I have everything configured and working on our test bench except for SIP Forking/Shared Line Appearance.  Here is my setup:

     1. I have (3) Polycom VVX400 phones setup, each with their own unique primary DN assigned.  All calls to and from these DN's work just fine.

     2. I have a shared secondary DN assigned to all three phones.  The binding for this line in the softswitch is set to 3, and all three phones have successfully registered this line and I can place calls from this line.

     3.  Problem is inbound calls.  When I call this shared DN from another number, the assigned secondary DN rings on all three phones as I would expect, but when I go to pickup the call on one of the phones, the other two phones continue to ring.  I can only silence or reject the call on those phones.

I have pasted in a copy my NV3140 config.  I am hoping that someone has come across a similar issue and has found a workaround.

!

!

! ADTRAN, Inc. OS version R11.10.0.E

! Boot ROM version R11.5.0

! Platform: NetVanta 3140, part number 4700341F2

! Serial number CFG1438909

!

!

hostname "NV3140"

enable password md5 encrypted b3c68d161f1275d1dbdb066a621be135

!

!

clock timezone -6-Central-Time

!

ip subnet-zero

ip classless

ip routing

ipv6 unicast-routing

!

!

domain-proxy

domain-proxy failover

!

ip local policy route-map ProbeMap

!

no auto-config

!

event-history on

no logging forwarding

no logging email

!

no service password-encryption

!

username "********" password "*******"

!

!

ip firewall

ip firewall fast-nat-failover

ip firewall fast-allow-failover

no ip firewall alg msn

no ip firewall alg mszone

no ip firewall alg h323

!

!

!

!

!

!

!

!

!

no dot11ap access-point-control

!

!

!

probe PRIMARY_INTERNET icmp-echo

  destination 8.8.8.8

  period 3

  tolerance consecutive fail 5 pass 5

  no shutdown

!

track PRIMARY_TRACK

  test if probe PRIMARY_INTERNET

  no shutdown

!

!

!

!

ip dhcp excluded-address 192.168.2.1 192.168.2.10

ip dhcp excluded-address 192.168.1.1 192.168.1.10

!

ip dhcp pool "DATA"

  network 192.168.1.0 255.255.255.0

  dns-server 192.168.1.1

  default-router 192.168.1.1

!

ip dhcp pool "VOICE"

  network 192.168.2.0 255.255.255.0

  dns-server 192.168.2.1

  default-router 192.168.2.1

  ntp-server 192.168.2.1

  option 66 ip ********

  option 160 ascii tftp://********

!

!

!

!

!

!

!

!

!

!

!

qos map VoIP 10

  match dscp 46

  priority 2000 strict-rate-limiting

!

!

!

!

interface gigabit-eth 0/1

  encapsulation 802.1q

  bandwidth 20000

  traffic-shape rate 20000000

  no shutdown

!

interface gigabit-eth 0/1.200

  vlan-id 200

  ip address dhcp track PRIMARY_TRACK

  ip access-policy Public

  no shutdown

interface gigabit-eth 0/1.3003

  vlan-id 3003

  ip address  ********

  ip access-policy VoIP

  media-gateway ip primary

  no shutdown

!

interface gigabit-eth 0/2

  encapsulation 802.1q

  no shutdown

!

interface gigabit-eth 0/2.1

  vlan-id 1 native

  ip address  192.168.1.1  255.255.255.0

  ip access-policy DATA-LAN

  no shutdown

interface gigabit-eth 0/2.2

  vlan-id 2

  ip address  192.168.2.1  255.255.255.0

  ip access-policy VOICE-LAN

  media-gateway ip primary

  no shutdown

!

interface gigabit-eth 0/3

  no ip address

  shutdown

!

!

!

interface cellular 0/1

  resource pool-member CELLULAR 1

  no shutdown

!

interface demand 1 encapsulation hdlc

  idle-timeout 600

  resource pool CELLULAR

  match-interesting ip list PermitAny out

  match-interesting ip reverse list PermitAny in

  connect-sequence 1 dial-string #777 forced-cellular

  connect-sequence attempts 0

  connect-sequence interface-recovery

  connect-mode originate

  description Cellular Demand Interface

  ip address cellular

  ip access-policy PublicCellular

  no shutdown

!

!

route-map ProbeMap permit 10

  match ip address ProbeTest

  set interface gigabit-ethernet 0/1.200

!

!

!

!

ip access-list extended AdminAccess

  permit tcp any  any eq ssh 

  permit tcp any  any eq https 

!

ip access-list extended PermitAny

  permit ip any  any   

!

ip access-list extended ProbeTest

  permit icmp any  host 8.8.8.8   

!

ip access-list extended VoIP

  permit udp 10.0.0.0 0.255.255.255  any eq 5060  

!

!

!

!

ip policy-class DATA-LAN

  allow list self self

  nat source list PermitAny interface gigabit-ethernet 0/1.200 overload policy P

  allow list self self

  nat source list PermitAny interface gigabit-ethernet 0/1.200 overload policy Public

  nat source list PermitAny interface demand 1 overload policy PublicCellular

!

ip policy-class Public

  allow list AdminAccess self

!

ip policy-class PublicCellular

  allow list AdminAccess self

!

ip policy-class VOICE-LAN

  allow list self self

  nat source list PermitAny interface gigabit-ethernet 0/1.3003 overload

!

ip policy-class VoIP

  allow list VoIP

!

!

!

ip route 0.0.0.0 0.0.0.0 demand 1 10

ip route ********

ip route ********

!

no tftp server

no tftp server overwrite

http server

http secure-server

no snmp agent

no ip ftp server

no ip scp server

ip sntp server

!

!

!

!

!

!

!

!

sip

sip udp 5060

no sip tcp

!

!

!

voice feature-mode network

voice forward-mode network

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

sip proxy

sip proxy transparent

!

sip proxy domain "sip.ptcnet.net"

sip proxy duplicates-allowed

sip proxy grammar request-uri host domain

sip proxy grammar to host domain

sip proxy grammar from host domain

sip proxy grammar proxy-id contact-user

!

sip proxy sip-server primary ********

sip proxy sip-server secondary ********

sip proxy sip-server rollover service-unavailable-or-timeout

!

!

!

sip proxy failover accept-registrations

sip proxy failover match-digits 4

!

!

!

!

!

!

!

!

!

!

!

line con 0

  no login

!

line telnet 0 4

  login local-userlist

  no shutdown

line ssh 0 4

  login local-userlist

  no shutdown

!

sntp server pool.ntp.org

!

!

!

!

end

[jayh]

If you dial the shared secondary number from outside and hang up (abandon the call) before answering any of the phones, do they all stop ringing immediately?

If you pick up one of the ringing phones after answering it on another, what do you get? Dead air? Bridged into call? Dial tone?

This sounds like an issue with the Genband. They should be sending a CANCEL and seeing a response of 487 Request Terminated on the remaining shared call appearances when the first one is answered. SIP debugs may help here.

[Anonymous]

If I call the shared line from an outside line (and do not answer any of the phones) the Polycom phones continue to ring for a period of time even after I hang up the phone from where I placed the call.

If I answer the call on one of the Polycom phones and then pick up one of the other phones that are ringing, the phone just continues to ring.  I cannot pickup the ringing line.  The only way I can stop the ringing is to hit "Silence" or "Reject" on the phone display. 

I have attached some debugs that I captured and sent into support.  I was told by the support agent I spoke with that he was not sure the NetVanta supported sip forking in a sip proxy environment and that engineering would have to take a look at it.

I did attach a printout of my sip proxy database and of some sip debugs if you would care to take a look.  My three Polycom phones are x1234, x1235, and x8999.  They all have a shared line of 1230, which is the line I'm having issues with.

[jayh]

The method you're trying to implement of handling shared call appearances in this scenario is different than I've seen and likely to give trouble. You have identical line appearances on three phones going through the Adtran device. The Genband will treat this as one endpoint and things won't work as you intended.

The usual way to do this is for each phone with a shared call appearance to register through the proxy with a unique username. The Genband will then handle the logic of which phone(s) to ring and when to stop. This is far more flexible as you can have sequential as well as simultaneous calling. Each shared call appearance would register uniquely, for example sca4023471230-1, sca4023471230-2 and sca4023471230-3 in your case. Each registration gets proxied separately. The Genband is programmed to ring them as as simultaneous hunt group. When any one answers, a CANCEL is sent to the others.

The problem with your setup that a SIP CANCEL is substantially different from a SIP BYE. The CANCEL is sent only on calls that aren't answered. Because the call *is* answered, when the CANCEL arrives the Adtran doesn't know how to handle it and rejects it with a 481 call leg does not exist and a 503 server error. Thus it never reaches the other phones. When you try to pick up, because the call is already answered, the media never gets negotiated  and the phone keeps ringing. You can see the misbehavior of CANCEL handling in your log starting at timestamp11:17:45.319 .

Another possibility would be to treat the line appearances locally as a ring group by having the phones register to the Adtran directly with unique usernames instead of being proxied. Then treat the secondary DID as the pilot of the ring group. I haven't tried this. In any case you will need each shared line appearance to have a unique username.

Registering them as unique usernanes to the Genband and having the Genband treat them as a simul-ring hunt group is cleaner and more scalable in my opinion.

[Anonymous]

I follow what you are saying, but I'm not sure that the Genband C15 will allow me to do that.  I can create three separate SIP lines w/ unique usernames as you've stated above, but the only way to assign those lines to my phones would be to make those lines appear as a MADN (Multi Appearance Directory Number).  Using a MADN solves the ringing issue, however, once the line is in use by one phone, it is then restricted to that phone only.  No other calls can be placed to or from a MADN line while an active call is taking place.

My hunt groups on the C15 also do not allow a simultaneous ring.  I can only do a sequential, circular, or rotary ring pattern. 

[jayh]

I'd address the issue with Genband. It's not an Adtran problem. Voice switch manufacturers have different names for similar features, but any reasonable switch should be able to give you the functionality you desire. Explain what you're trying to do and they should tell you their name for that feature and how to make it work.

[Anonymous]

I have a ticket open with support on this.  This must be something that they want to address.  They registered a few phones from their lab directly to my softswitch and must have verified an issue as I got a response saying that they are looking to resolve the issue in the next extended maintenance release, R11.10.6 which is scheduled for December.