Understand CUSP Terminology and Routing Logic

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Updated:September 29, 2017

Document ID:212177

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Introduction

This document explains how Cisco Unified SIP Proxy (CUSP) call routing logic.

Contributed by Joshua Meadows, Cisco TAC Engineer.

Prerequisites

Requirements

Cisco recommends that you have the knowledge of these topics:

General knowledge of Session Initiation Protocol (SIP)
Conceptual Understanding of CUSP in voice network deployments

Terminology

Definitions

Term	Definition
Network	A SIP network is a logical collection of local interfaces that can be treated the same for general routing purposes. From <http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cusp/rel9_1/gui_configuration/en_US/configuring_networks.html> The Network logically defines areas of the network. The network can be defined using interfaces on the CUSP device, or specific ports can be used to provide segmentation. To achieve this logical segmentation, separate Listen Ports can be configured. (Example: Listen Ports 14.50.245.9:5060, 14.50.245.9:5062, 14.50.245.9:5065 can define three logical networks using a single CUSP layer 3 interface) Once the Networks are defined logically, they can be used to configured Triggers based on the Network. Note: If you set up a listen port, ensure devices sending traffic to the CUSP use the correct port. If you set up listen port 14.50.245.9:5065 for CUCM traffic, you must ensure CUCM sends traffic to port 5065, not the default of 5060.
Triggers	Triggers can be set to identify incoming messages. Triggers can identify Inbound Network, Local Port, Remote Network, etc.
Server Group	Server groups define the elements with which the Cisco Unified SIP Proxy system interacts for each network. From <http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cusp/rel9_1/gui_configuration/en_US/configuring_server_groups.html> Both Server Group and Route Group can be used as destinations in the Route Table. A server group would generally be used for redundant devices of the same type. A CUBE stack would be a good example of a Server Group.
Route Group	A route group allows you to designate the order in which gateways and trunks are selected. It allows you to prioritize a list of gateways and ports for outgoing trunk selection. From <http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cusp/rel9_1/gui_configuration/en_US/configuring_route_groups.html> Both Server Group and Route Group can be used as destinations in the Route Table. A route group generally defines a weighted group destinations to reach the same device. A direct SIP trunk to a CUCM and a SIP trunk to a PSTN gateway to reach the CUCM would be a good example of a Route Group. The direct SIP trunk to the CUCM would be the prefered method, and the PSTN route would be a backup.
Route Table	You configure route tables to direct SIP requests to their appropriate destinations. Each route table consists of a set of keys that are matched based on the lookup policy. From <http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cusp/rel9_1/gui_configuration/en_US/configuring_route_tables.html> Route Tables in CUSP are similar to Layer 3 routing tables. CUSP Route Tables consist of Keys similar to networks in layer 3 routing tables. Route Tables link Keys to destinations. In the CUSP Route Table Keys can be mapped to the following route types to route SIP messages: destination: a specific host or a locally configured server group can be configured as a destination route-group: a locally configured route-group with one or more elements route-policy: route policies can be used to move between Route Tables similar to translation patterns in CUCM reponse: rather than routing a SIP message, CUSP can send a specific response to terminate the call attempt default-sip: Simple routing following RFC 3263. Note: If mapping a Key to a route-policy, be cognizant of logical loops.
Route Policy	A Route Policy points to a a Route Table and defines how to use the Key in that route table. Example: Route Table Name: "FromCUCM105-RT" Lookup Key matches: "Prefix-Longest-Match" Lookup Key: "SIP Header: 'To' Phone" By separating the definition of the Key from the configured value of the Key the same Route Table can be used in different ways. For example, one Route Policy could define the Route Table's Key as the prefix for a TO: header, while another Route Policy could define the Route Table's Key as the prefix for a FROM: header.
Routing Triggers	Routing Triggers link a Trigger to a Route Policy. Logically it states if a SIP message matches the Trigger, then use the configured Route Policy.

In summation, a SIP message is tagged with a Network based on the SIP listen port. The Network can be used to match a Trigger. The Route Policy then identifies which Route Table to use based on the Trigger and defines where to look for the Key. The Route Table will then use the Key to find out where to route the SIP message (Route Type). The Route Type (Host, Server Group, Route Group, etc) will be used to send the SIP message to the configured destination (element).

Network Topology

Call Example

Call from PSTN 1001 to 2003 on CUCM115

Basic Call Routing

Incoming Network: “PSTN”

Trigger: “From-PSTN-Trigger”

Triggers if incoming message matched Network “PSTN”

Routing Trigger: “FromPSTN-RPolicy” “From-PSTN-Trigger”

Links “From-PSTN-Trigger” to “FromPSTN-RPolicy”

Route Policy: “FromPSTN-RPolicy”

Specifies Routing table “PSTN-RT”

Specifies Lookup Key Matches “Prefix-Longest-Match”

Specifies Lookup Key is “SIP Header: 'To' Phone”

Route Table: “PSTN-RT”

Contains Key “2” to go to Route Group “CUCM115_RG”

Route Group (or Server Group): “CUCM115_RG”

Contains Element 14.50.245.20:5065

These configurations combine to make the logical statement:

For a call from the PSTN, where phone number prefix is 2, route to 14.50.245.20:5065

Configurations

PSTN - 2XXX and 5XXX calls are sent to CUSP via the CUBE and vCUBE

CUCM 10.5 - 1XXX and 2XXX are sent to CUSP via SIP trunk

CUCM 11.5 - 1XXX and 5XXX are sent to CUSP via SIP trunk

Note: When using the GUI, some configurations must be committed before they are available in other configuration sections. These are marked with ###Commit Configuration

Key Configuration Elements

CLI Configuration	GUI Configuration
Create a Network
sip network PSTN standard	Configure >> Networks >> Add
Define listening port to identify network 'PSTN'
sip listen PSTN udp 14.50.245.9 5060	Configure >> Networks >> [Network Name] >> SIP Listen Points >> Add
Trigger for Inbound Network 'PSTN'
trigger condition From-PSTN-Trigger sequence 1 in-network ^\QPSTN\E$ end sequence end trigger condition	Configure >> Triggers >> Add Configure Trigger Name Configure Trigger Condition and click add
Specify a destination for 'CUCM115_RG'
route group CUCM115_RG element target-destination 14.50.245.20:5065:udp CUCM115 q-value 0.0 failover-codes 502 - 503 weight 50 end element end route	Configure >> Route Groups >> Add (###Commit Configuration) Configure a Route Group Name Click "Click Here" under Elements Column, then Click Add Enter the Element Destination
Define Route Table and associate a key to a destination
route table PSTN-RT key 2 group CUCM115_RG key 5 group CUCM105_RG end route table	Configure >> Route Tables >> Add (###Commit Configuration) Configure a Route Table name Enter a Key and Destination When configuring a Route Group as a destination in a Route Table, do NOT add a port and transport type. By adding a Port and/or Transport type, you are telling CUSP to look for DNS Host entry Cubestack:5060:UDP rather than looking in the locally significant Server Group configurations.
Define the Key for 'FromPSTN-RPolicy'
policy lookup FromPSTN-RPolicy sequence 100 PSTN-RT header to uri-component phone rule prefix end sequence end policy	Configure >> Route Policies >> Add (###Commit Configuration) Configure a Route Policy name Click Add to add a Policy Step The policy step will define how the Key is used. In this case, the policy looks for the longest Phone number match on the To: field in the SIP header
Link the 'From-PSTN-Trigger' to 'FromPSTN-RPolicy'
trigger routing sequence 2 policy FromPSTN-RPolicy condition From-PSTN-Trigger	Configure >> Routing Triggers >> Add Select a Routing Policy to link to a Trigger

Full Configuration

Note: show configuration active verbose will show the entire configuration including the Route Tables.

josmeado-CUSP(cusp)# show configuration active verbose
Building CUSP configuration...
!
server-group sip global-load-balance weight
server-group sip retry-after 250
server-group sip element-retries udp 2
server-group sip element-retries tls 1
server-group sip element-retries tcp 1
sip dns-srv
 enable
 no naptr
 end dns
!
no sip header-compaction
no sip logging
!
sip max-forwards 70
sip network CUCM105 standard
 no non-invite-provisional
 allow-connections
 no tls verify
 retransmit-count invite-client-transaction 3
 retransmit-count invite-server-transaction 5
 retransmit-count non-invite-client-transaction 3
 retransmit-timer T1 500
 retransmit-timer T2 4000
 retransmit-timer T4 5000
 retransmit-timer TU1 5000
 retransmit-timer TU2 32000
 retransmit-timer clientTn 64000
 retransmit-timer serverTn 64000
 tcp connection-setup-timeout 1000
 tls handshake-timeout 3000
 udp max-datagram-size 1500
 end network
!
sip network CUCM115 standard
 no non-invite-provisional
 allow-connections
 no tls verify
 retransmit-count invite-client-transaction 3
 retransmit-count invite-server-transaction 5
 retransmit-count non-invite-client-transaction 3
 retransmit-timer T1 500
 retransmit-timer T2 4000
 retransmit-timer T4 5000
 retransmit-timer TU1 5000
 retransmit-timer TU2 32000
 retransmit-timer clientTn 64000
 retransmit-timer serverTn 64000
 tcp connection-setup-timeout 1000
 tls handshake-timeout 3000
 udp max-datagram-size 1500
 end network
!
sip network PSTN standard
 no non-invite-provisional
 allow-connections
 no tls verify
 retransmit-count invite-client-transaction 3
 retransmit-count invite-server-transaction 5
 retransmit-count non-invite-client-transaction 3
 retransmit-timer T1 500
 retransmit-timer T2 4000
 retransmit-timer T4 5000
 retransmit-timer TU1 5000
 retransmit-timer TU2 32000
 retransmit-timer clientTn 64000
 retransmit-timer serverTn 64000
 tcp connection-setup-timeout 1000
 tls handshake-timeout 3000
 udp max-datagram-size 1500
 end network
!
sip overload reject retry-after 0
!
no sip peg-counting
!
sip privacy service
sip queue message
 drop-policy head
 low-threshold 80
 size 2000
 thread-count 20
 end queue
!
sip queue radius
 drop-policy head
 low-threshold 80
 size 2000
 thread-count 20
 end queue
!
sip queue request
 drop-policy head
 low-threshold 80
 size 2000
 thread-count 20
 end queue
!
sip queue response
 drop-policy head
 low-threshold 80
 size 2000
 thread-count 20
 end queue
!
sip queue st-callback
 drop-policy head
 low-threshold 80
 size 2000
 thread-count 10
 end queue
!
sip queue timer
 drop-policy none
 low-threshold 80
 size 2500
 thread-count 8
 end queue
!
sip queue xcl
 drop-policy head
 low-threshold 80
 size 2000
 thread-count 2
 end queue
!
route recursion
!
sip tcp connection-timeout 30
sip tcp max-connections 256
!
no sip tls
!
sip tls connection-setup-timeout 1
!
trigger condition From-CUCM105-Trigger
 sequence 1
  in-network ^\QCUCM105\E$
  end sequence
 end trigger condition
!
trigger condition From-CUCM115-Trigger
 sequence 1
  in-network ^\QCUCM115\E$
  end sequence
 end trigger condition
!
trigger condition From-PSTN-Trigger
 sequence 1
  in-network ^\QPSTN\E$
  end sequence
 end trigger condition
!
trigger condition mid-dialog
 sequence 1
  mid-dialog
  end sequence
 end trigger condition
!
accounting
 no enable
 no client-side
 no server-side
 end accounting
!
server-group sip group Cubestack PSTN
 element ip-address 14.50.245.6 5060 udp q-value 0.0 weight 1
 element ip-address 14.50.245.7 5060 udp q-value 0.0 weight 1
 failover-resp-codes 503
 lbtype weight
 ping
 end server-group
!
route group CUCM105_RG
 element target-destination 14.50.245.25:5062:udp CUCM105 q-value 0.0
  failover-codes 510
  weight 50
  end element
 end route
!
route group CUCM115_RG
 element target-destination 14.50.245.20:5065:udp CUCM115 q-value 0.0
  failover-codes 502 - 503
  weight 50
  end element
 end route
!
route table FromCUCM105-RT
 key * target-destination Cubestack PSTN
 key 2 group CUCM115_RG
 end route table
!
route table FromCUCM115-RT
 key 1 target-destination Cubestack PSTN
 key 5 group CUCM105_RG
 end route table
!
route table PSTN-RT
 key 2 group CUCM115_RG
 key 5 group CUCM105_RG
 end route table
!
policy lookup FromCUCM105-RPolicy
 sequence 100 FromCUCM105-RT header to uri-component phone
  rule prefix
  end sequence
 end policy
!
policy lookup FromCUCM115-RPolicy
 sequence 100 FromCUCM115-RT header to uri-component phone
  rule prefix
  end sequence
 end policy
!
policy lookup FromPSTN-RPolicy
 sequence 100 PSTN-RT header to uri-component phone
  rule prefix
  end sequence
 end policy
!
trigger routing sequence 1 by-pass condition mid-dialog
trigger routing sequence 2 policy FromPSTN-RPolicy condition From-PSTN-Trigger
trigger routing sequence 3 policy FromCUCM115-RPolicy condition From-CUCM115-Trigger
trigger routing sequence 4 policy FromCUCM105-RPolicy condition From-CUCM105-Trigger
!
server-group sip global-ping
!
no server-group sip ping-503
!
sip cac session-timeout 720
sip cac PSTN 14.50.245.6 5060 udp limit -1
sip cac PSTN 14.50.245.7 5060 udp limit -1
!
no sip cac
!
sip listen CUCM105 udp 14.50.245.9 5062
sip listen CUCM115 udp 14.50.245.9 5065
sip listen PSTN udp 14.50.245.9 5060
!
call-rate-limit 100
!
end

Troubleshoot

Trace Levels Configuration

In the CUSP GUI, navigate to Troubleshoot >> Cisco Unified SIP Proxy >> Traces

Trigger-Conditions - Level:debug: This will show which triggers were match to initate call routing.

Routing - Level:debug: This will show what was done during call routing. Which Key's were matched, what destination was chosen, etc.

SIP-Wire-Log - Level:debug: This will show the SIP messages received and sent.

Trace Collection

Via GUI

In the CUSP GUI, navigate to Troubleshoot >> Cisco Unified SIP Proxy >> Traces

Select Download Log File

You can also Clear Logs

Via FTP Client

By default there is no account with FTP privilages. To enable an account with FTP privilages add the user to a PFS group.

josmeado-CUSP# user platformadmin group ?
  Administrators    System administrators group
  pfs-privusers     PFS privileged users group
  pfs-readonly      PFS read only group
josmeado-CUSP# user platformadmin group pfs

Via FTP Client, connect to CUSP. File Path: cusp >> log >> trace >> trace.log

Trace Order

SIP-Wire-Log - Incoming SIP Invite
SIP-Wire-Log - Return 100 Trying
Trigger-Condition - Identify Network and Trigger Route Policy
Routing - See Routing Trace section below for details
SIP-Wire-Log - Send Invite toward destination
SIP-Wire-Log - Continue normal SIP transactions until there is a 200 Ok message for each call leg

Trigger-Condition Trace Sample

13:24:36:987 08:17:2017 vCUSP,9.1.5,josmeado-CUSP,14.50.245.9,trace.log
[REQUESTI.7] DEBUG 2017.08.17 13:25:03:006 conditions.RegexCondition - inNetwork='PSTN'
[REQUESTI.7] DEBUG 2017.08.17 13:25:03:006 conditions.RegexCondition - IN_NETWORK: PSTN
[REQUESTI.7] DEBUG 2017.08.17 13:25:03:006 conditions.AbstractRegexCondition - pattern(^\QPSTN\E$), toMatch(PSTN) returning true
[REQUESTI.7] DEBUG 2017.08.17 13:25:03:006 triggers.ModuleTrigger - ModuleTrigger.eval() action<FromPSTN-RPolicy> actionParameter<>
[REQUESTI.7] DEBUG 2017.08.17 13:25:03:006 triggers.ModuleTrigger - ModuleTrigger.eval() got the policy, executing it ...

In the above sample, we see the network is matched as PSTN, which is used in Route Policy "FromPSTN-RPolicy".

Routing Trace Sample

13:29:13:453 08:17:2017 vCUSP,9.1.5,josmeado-CUSP,14.50.245.9,trace.log
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 nrs.XCLNRSShiftRoutes - Entering ShiftAlgorithms.execute()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 nrs.XCLNRSShiftRoutes - Leaving ShiftAlgorithms.execute()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 modules.XCLLookup - Entering execute()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 nrs.XCLPrefix - Entering getKeyValue()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 nrs.FieldSelector - getToUri: To header obtained - To: <sip:2003@14.50.245.9>

[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 nrs.FieldSelector - getUriPart: URI - sip:2003@14.50.245.9 part 1
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 nrs.FieldSelector - Requested field 52
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 nrs.FieldSelector - Returning key 2003
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 nrs.XCLPrefix - Leaving getKeyValue()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 modules.XCLLookup - table=PSTN-RT, key=2003
[REQUESTI.7] INFO  2017.08.17 13:29:33:987 modules.XCLLookup - table is PSTN-RT
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 routingtables.RoutingTable - Entering lookup()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 routingtables.RoutingTable - Looking up 2003 in table PSTN-RT with rule prefix and modifiers=none
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 routingtables.RoutingTable - Entering applyModifiers()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:987 routingtables.RoutingTable - Leaving applyModifiers(), returning 2003
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 routingtables.RoutingTable - Leaving lookup()
[REQUESTI.7] INFO  2017.08.17 13:29:33:988 nrs.XCLPrefix - NRS Routing decision is: RouteTable:PSTN-RT, RouteKey:2, RouteGroup:CUCM115_RG
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 loadbalancer.LBFactory - Entering createLoadBalancer()
[REQUESTI.7] INFO  2017.08.17 13:29:33:988 loadbalancer.LBFactory - lbtype is 3(call-id)
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 loadbalancer.LBFactory - Leaving createLoadBalancer()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 nrs.XCLPrefix - Stored NRSAlgResult=isFound=true, isFailure=false, Response=-1, Routes=[Ruri: 14.50.245.20:5065:udp, Route: null, Network: CUCM115, q-value=0.0radvance=[502, 503]], PolicyAdvance=null
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 nrs.NRSAlgResult - set policyAdvance as specified in route=RouteTable:PSTN-RT, RouteKey:2, RouteGroup:CUCM115_RG
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 nrs.NRSAlgResult - no policyAdvance specified in route
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 nrs.NRSAlgResult - set policyAdvance as specified in algorithm={lookuprule=1, lookupfield=52, lookuplenght=-1, lookuptable=PSTN-RT, sequence=100, algorithm=1}
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 nrs.NRSAlgResult - no policyAdvance specified in algorithm
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 modules.XCLLookup - Leaving execute()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 nrs.XCLNRSShiftRoutes - Entering ShiftRoutes.execute()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 loadbalancer.LBBase - Entering getServer()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 loadbalancer.LBBase - Entering initializeDomains()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 nrs.NRSRoutes - routes before applying time policies: [Ruri: 14.50.245.20:5065:udp, Route: null, Network: CUCM115, q-value=0.0radvance=[502, 503]]
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 nrs.NRSRoutes - routes after applying time policies: [Ruri: 14.50.245.20:5065:udp, Route: null, Network: CUCM115, q-value=0.0radvance=[502, 503]]
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 loadbalancer.LBBase - Leaving initializeDomains()
[REQUESTI.7] INFO  2017.08.17 13:29:33:988 loadbalancer.LBHashBased - list of elements in order on which load balancing is done : Ruri: 14.50.245.20:5065:udp, Route: null, Network: CUCM115, q-value=0.0radvance=[502, 503], 
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 loadbalancer.LBBase - Server group route-sg selected Ruri: 14.50.245.20:5065:udp, Route: null, Network: CUCM115, q-value=0.0radvance=[502, 503]
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 loadbalancer.LBBase - Leaving getServer()
[REQUESTI.7] DEBUG 2017.08.17 13:29:33:988 nrs.XCLNRSShiftRoutes - Leaving ShiftRoutes.execute()

1. CUSP gets the Key value in the TO: header

2. CUSP identifies the Key as 2003

3. CUSP Looks up the Key in the Routing Table

4. CUSP matches an entry in the Routing Table and identifies destination RouteGroup:CUCM115_RG

5. CUSP applies loadbalancing within teh RouteGroup

6. CUSP identifies the specific Element in the RouteGroup to which it will send the SIP message

7. CUSP applies Time Policies if applicable

8. CUSP finalizes the Element to which it will send a SIP Message

SIP-Wire-Log Trace Sample

13:48:26:669 08:17:2017 vCUSP,9.1.5,josmeado-CUSP,14.50.245.9,trace.log
[DsTransportListener-2] DEBUG 2017.08.17 13:48:52:221 DsSipLlApi.Wire - Received UDP packet on 14.50.245.9:5060 ,source 14.50.245.6:50683
INVITE sip:2003@14.50.245.9:5060 SIP/2.0
Via: SIP/2.0/UDP 14.50.245.6:5060;branch=z9hG4bK2A5763
Remote-Party-ID: <sip:1001@14.50.245.6>;party=calling;screen=no;privacy=off
From: <sip:1001@14.50.245.6>;tag=4E329FEC-A9F
To: <sip:2003@14.50.245.9>
Date: Thu, 17 Aug 2017 13:48:52 GMT
Call-ID: 2A7BE22B-82AB11E7-83AEAE0B-F940DC75@14.50.245.6
Supported: 100rel,timer,resource-priority,replaces,sdp-anat
Min-SE:  1800
Cisco-Guid: 0350227076-2191790567-2162465606-1670485135
User-Agent: Cisco-SIPGateway/IOS-15.5.3.S4b
Allow: INVITE, OPTIONS, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY, INFO, REGISTER
CSeq: 101 INVITE
Timestamp: 1502992132
Contact: <sip:1001@14.50.245.6:5060>
Expires: 180
Allow-Events: telephone-event
Max-Forwards: 69
Content-Type: application/sdp
Content-Disposition: session;handling=required
Content-Length: 266

v=0
o=CiscoSystemsSIP-GW-UserAgent 7317 4642 IN IP4 14.50.245.6
s=SIP Call
c=IN IP4 14.50.245.6
t=0 0
m=audio 8266 RTP/AVP 18 127
c=IN IP4 14.50.245.6
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=rtpmap:127 telephone-event/8000
a=fmtp:127 0-16
a=ptime:20

--- end of packet ---

[REQUESTI.7] DEBUG 2017.08.17 13:48:52:223 DsSipLlApi.Wire - Sending UDP packet on 14.50.245.9:32789, destination 14.50.245.6:5060
SIP/2.0 100 Trying
Via: SIP/2.0/UDP 14.50.245.6:5060;branch=z9hG4bK2A5763
To: <sip:2003@14.50.245.9>
From: <sip:1001@14.50.245.6>;tag=4E329FEC-A9F
Call-ID: 2A7BE22B-82AB11E7-83AEAE0B-F940DC75@14.50.245.6
CSeq: 101 INVITE
Timestamp: 1502992132
Content-Length: 0


[REQUESTI.7] DEBUG 2017.08.17 13:48:52:225 DsSipLlApi.Wire - Sending UDP packet on 14.50.245.9:32790, destination 14.50.245.20:5065
INVITE sip:2003@14.50.245.20:5065;transport=udp SIP/2.0
Via: SIP/2.0/UDP 14.50.245.9:5065;branch=z9hG4bKM3X51yKL9BEW5v0Kudc5Dw~~128
Via: SIP/2.0/UDP 14.50.245.6:5060;branch=z9hG4bK2A5763
Max-Forwards: 68
To: <sip:2003@14.50.245.9>
From: <sip:1001@14.50.245.6>;tag=4E329FEC-A9F
Contact: <sip:1001@14.50.245.6:5060>
Expires: 180
Remote-Party-ID: <sip:1001@14.50.245.6>;party=calling;screen=no;privacy=off
Call-ID: 2A7BE22B-82AB11E7-83AEAE0B-F940DC75@14.50.245.6
CSeq: 101 INVITE
Content-Length: 266
Date: Thu, 17 Aug 2017 13:48:52 GMT
Supported: 100rel,timer,resource-priority,replaces,sdp-anat
Min-SE: 1800
Cisco-Guid: 0350227076-2191790567-2162465606-1670485135
User-Agent: Cisco-SIPGateway/IOS-15.5.3.S4b
Allow: INVITE, OPTIONS, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY, INFO, REGISTER
Timestamp: 1502992132
Allow-Events: telephone-event
Content-Type: application/sdp
Content-Disposition: session;handling=required

v=0
o=CiscoSystemsSIP-GW-UserAgent 7317 4642 IN IP4 14.50.245.6
s=SIP Call
c=IN IP4 14.50.245.6
t=0 0
m=audio 8266 RTP/AVP 18 127
c=IN IP4 14.50.245.6
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=rtpmap:127 telephone-event/8000
a=fmtp:127 0-16
a=ptime:20

[DsTransportListener-3] DEBUG 2017.08.17 13:48:52:229 DsSipLlApi.Wire - Received UDP packet on 14.50.245.9:5065 ,source 14.50.245.20:5065
SIP/2.0 100 Trying
Via: SIP/2.0/UDP 14.50.245.9:5065;branch=z9hG4bKM3X51yKL9BEW5v0Kudc5Dw~~128,SIP/2.0/UDP 14.50.245.6:5060;branch=z9hG4bK2A5763
From: <sip:1001@14.50.245.6>;tag=4E329FEC-A9F
To: <sip:2003@14.50.245.9>
Date: Thu, 17 Aug 2017 17:48:52 GMT
Call-ID: 2A7BE22B-82AB11E7-83AEAE0B-F940DC75@14.50.245.6
CSeq: 101 INVITE
Allow-Events: presence
Content-Length: 0


--- end of packet ---

[DsTransportListener-3] DEBUG 2017.08.17 13:48:52:284 DsSipLlApi.Wire - Received UDP packet on 14.50.245.9:5065 ,source 14.50.245.20:5065
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP 14.50.245.9:5065;branch=z9hG4bKM3X51yKL9BEW5v0Kudc5Dw~~128,SIP/2.0/UDP 14.50.245.6:5060;branch=z9hG4bK2A5763
From: <sip:1001@14.50.245.6>;tag=4E329FEC-A9F
To: <sip:2003@14.50.245.9>;tag=93896~37db7c49-96d4-4c4c-a223-626b2c74c16a-16919968
Date: Thu, 17 Aug 2017 17:48:52 GMT
Call-ID: 2A7BE22B-82AB11E7-83AEAE0B-F940DC75@14.50.245.6
CSeq: 101 INVITE
Allow: INVITE, OPTIONS, INFO, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY
Allow-Events: presence
Server: Cisco-CUCM11.5
Call-Info: <urn:x-cisco-remotecc:callinfo>;x-cisco-video-traffic-class=DESKTOP
Supported: X-cisco-srtp-fallback
Supported: Geolocation
Session-ID: 1e6e772300105000a00084b517ae1a83;remote=c07cdfa83b8f7c373757cf842ab93896
P-Asserted-Identity: "Alerting JM1 - 2003" <sip:2003@14.50.245.20>
Remote-Party-ID: "Alerting JM1 - 2003" <sip:2003@14.50.245.20>;party=called;screen=yes;privacy=off
Contact: <sip:2003@14.50.245.20:5065>;+u.sip!devicename.ccm.cisco.com="SEP84B517AE1A83"
Content-Length: 0


--- end of packet ---

[CT_CALLBACK.15] DEBUG 2017.08.17 13:48:52:285 DsSipLlApi.Wire - Sending UDP packet on 14.50.245.9:32789, destination 14.50.245.6:5060
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP 14.50.245.6:5060;branch=z9hG4bK2A5763
To: <sip:2003@14.50.245.9>;tag=93896~37db7c49-96d4-4c4c-a223-626b2c74c16a-16919968
From: <sip:1001@14.50.245.6>;tag=4E329FEC-A9F
Contact: <sip:2003@14.50.245.20:5065>;+u.sip!devicename.ccm.cisco.com="SEP84B517AE1A83"
Remote-Party-ID: "Alerting JM1 - 2003" <sip:2003@14.50.245.20>;party=called;screen=yes;privacy=off
Call-ID: 2A7BE22B-82AB11E7-83AEAE0B-F940DC75@14.50.245.6
CSeq: 101 INVITE
Content-Length: 0
Date: Thu, 17 Aug 2017 17:48:52 GMT
Allow: INVITE, OPTIONS, INFO, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY
Allow-Events: presence
Server: Cisco-CUCM11.5
Call-Info: <urn:x-cisco-remotecc:callinfo>;x-cisco-video-traffic-class=DESKTOP
Supported: X-cisco-srtp-fallback
Supported: Geolocation
Session-ID: 1e6e772300105000a00084b517ae1a83;remote=c07cdfa83b8f7c373757cf842ab93896
P-Asserted-Identity: "Alerting JM1 - 2003" <sip:2003@14.50.245.20>


[DsTransportListener-3] DEBUG 2017.08.17 13:48:54:292 DsSipLlApi.Wire - Received UDP packet on 14.50.245.9:5065 ,source 14.50.245.20:5065
SIP/2.0 200 OK
Via: SIP/2.0/UDP 14.50.245.9:5065;branch=z9hG4bKM3X51yKL9BEW5v0Kudc5Dw~~128,SIP/2.0/UDP 14.50.245.6:5060;branch=z9hG4bK2A5763
From: <sip:1001@14.50.245.6>;tag=4E329FEC-A9F
To: <sip:2003@14.50.245.9>;tag=93896~37db7c49-96d4-4c4c-a223-626b2c74c16a-16919968
Date: Thu, 17 Aug 2017 17:48:52 GMT
Call-ID: 2A7BE22B-82AB11E7-83AEAE0B-F940DC75@14.50.245.6
CSeq: 101 INVITE
Allow: INVITE, OPTIONS, INFO, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY
Allow-Events: presence, kpml
Supported: replaces
Server: Cisco-CUCM11.5
Call-Info: <urn:x-cisco-remotecc:callinfo>;x-cisco-video-traffic-class=DESKTOP
Supported: X-cisco-srtp-fallback
Supported: Geolocation
Session-Expires:  1800;refresher=uas
Require:  timer
Session-ID: 1e6e772300105000a00084b517ae1a83;remote=c07cdfa83b8f7c373757cf842ab93896
P-Asserted-Identity: "CLID JM1 - 2003" <sip:2003@14.50.245.20>
Remote-Party-ID: "CLID JM1 - 2003" <sip:2003@14.50.245.20>;party=called;screen=yes;privacy=off
Contact: <sip:2003@14.50.245.20:5065>;+u.sip!devicename.ccm.cisco.com="SEP84B517AE1A83"
Content-Type: application/sdp
Content-Length: 258

v=0
o=CiscoSystemsCCM-SIP 93896 1 IN IP4 14.50.245.20
s=SIP Call
c=IN IP4 14.50.245.254
b=TIAS:8000
b=AS:8
t=0 0
m=audio 16502 RTP/AVP 18 101
a=ptime:20
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15

--- end of packet ---

[CT_CALLBACK.15] DEBUG 2017.08.17 13:48:54:293 DsSipLlApi.Wire - Sending UDP packet on 14.50.245.9:32789, destination 14.50.245.6:5060
SIP/2.0 200 OK
Via: SIP/2.0/UDP 14.50.245.6:5060;branch=z9hG4bK2A5763
To: <sip:2003@14.50.245.9>;tag=93896~37db7c49-96d4-4c4c-a223-626b2c74c16a-16919968
From: <sip:1001@14.50.245.6>;tag=4E329FEC-A9F
Contact: <sip:2003@14.50.245.20:5065>;+u.sip!devicename.ccm.cisco.com="SEP84B517AE1A83"
Require: timer
Remote-Party-ID: "CLID JM1 - 2003" <sip:2003@14.50.245.20>;party=called;screen=yes;privacy=off
Call-ID: 2A7BE22B-82AB11E7-83AEAE0B-F940DC75@14.50.245.6
CSeq: 101 INVITE
Content-Length: 258
Date: Thu, 17 Aug 2017 17:48:52 GMT
Allow: INVITE, OPTIONS, INFO, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY
Allow-Events: presence, kpml
Supported: replaces
Supported: X-cisco-srtp-fallback
Supported: Geolocation
Server: Cisco-CUCM11.5
Call-Info: <urn:x-cisco-remotecc:callinfo>;x-cisco-video-traffic-class=DESKTOP
Session-Expires: 1800;refresher=uas
Session-ID: 1e6e772300105000a00084b517ae1a83;remote=c07cdfa83b8f7c373757cf842ab93896
P-Asserted-Identity: "CLID JM1 - 2003" <sip:2003@14.50.245.20>
Content-Type: application/sdp

v=0
o=CiscoSystemsCCM-SIP 93896 1 IN IP4 14.50.245.20
s=SIP Call
c=IN IP4 14.50.245.254
b=TIAS:8000
b=AS:8
t=0 0
m=audio 16502 RTP/AVP 18 101
a=ptime:20
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15

SIP-Wire-Log shows the normal SIP messaging up to the 200 Okay for both call legs.

Architectural Reference

Contributed by Cisco Engineers

Joshua Meadows
Cisco TAC Engineer