Table of Contents
About this Page
This document outlines the SIP Message Manipulation feature.
Prerequisites
Assumes the user is familiar with configuring the SBCx000's WebUI
Requires Sonus SBC1000/2000 Version 2.2 or later
SMM Overview
Because you can never tell just what the other side of a SIP connection might send or need, the SBC1000/2000 version 2.2 includes a feature to manipulate any SIP header.
- SIP Headers can be added, deleted, or modified.
- Manipulation can be done for every SIP message, or separately for SIP Requests or SIP Responses.
- Manipulations can set to occur based upon user specified matching criteria.
- Manipulations can be executed at the ingress or egress SG.
- At the ingress, inbound SIP messages are modified to permit proper handling by the SBC's routing function.
- At the egress, SIP messages (already processed by the SBC) are modified to meet the SIP requirements of the upstream device.
The SMM feature is enabled on a Signaling Group. That means you can configure a SMM to change an incoming or outgoing SIP Message. It is important to note that SMM feature is separate from the SBC's SIP engine. SMM changes SIP Message either before they are processed, or after they are processed, by the SIP engine. In essence, SMM is not state aware.
For instance, if you were to change a FROM Tag on a 180 Ringing Message, the SIP engine would discard that 180 Ringing because it had a differernt Tag than all the previous SIP Messages. To the SIP engine, it would appear as if that 180 Ringing belonged to a different dialogue.
So, SMM changes must be made carefully to ensure that the SIP engine can still recognize that the messages are part of an ongoing dialogue.
What you will learn from this document...
- A SIP Refresher - the Anatomy of SIP Packets
- The 4 SIP Message Rules
- Mapping SIP Packet elements to their corresponding SMM configuration items
- Tokens - SMM's version of the Transformation Table
A SIP Refresher
In order to properly employ the SMM function, you need to understand the SIP protocol and packet syntax. With SMM its possible to change any portion of the SIP packet, so you best understand what's being changed!
Below is a brief SIP referesher, including:
- SIP Packet Types (requests vs. responses)
- Headers
- Parameters
Packet Types
SIP Requests are different than SIP Responses. In order to employ the SIP Manipulation function, you must know the difference between a Request and Response.
SIP Requests |
| SIP Responses (partial list) |
|---|---|---|
INVITE |
| 100 Trying |
ACK |
| 180 Ringing |
BYE |
| 183 Session Progressing |
CANCEL |
| 200 OK |
OPTIONS |
| 202 Accepted |
REGISTER |
| 302 Moved Temporarily |
PRACK |
| 400 Bad Request |
SUBSCRIBE |
| 401 Unauthorized |
NOTIFY |
| 403 Forbidden |
PUBLISH |
| 500 Server Internal Error |
INFO |
| 503 Service Unavailable |
REFER |
| 504 Server Timeout |
MESSAGE |
| 603 Decline |
UPDATE |
| 606 Message Too Large |
Anatomy of a SIP Packet
Knowing the separate parts of the SIP packet will help you use the correct section of the SMM Web UI. Request Line, Status Line, Headers, Header Parameters, URI and URI parameters are all portions of a SIP packet.
SIP Lines and Headers
SIP Packet Parameters
The 4 SIP Message Rules
Now that we're familiar with the anatomy of a SIP packet, let's examine the SMM Rules.
This diagram shows each type of SMM Rule and what portion of the SIP packet that type of rule affects.
Mapping of SMM Rule Types to Portions of SIP Messages
- Use Request Rules to change the Request URI Line
- Status Rules to change the Status Line
- Header Rules to change SIP headers
- Raw Rules to change SDP, or any portion of the SIP message not affected by other rules.
Mapping Sections of the SMM Rule to the SIP Packet
After selecting the appropriate Rule type, the Rule itself must be configured. Using the diagrams below, you can see which section of each rule corresponds with portions of a SIP message. Once you've identified what needs to be changed, consult the diagrams below to determine which configuration entry to employ to create the desired change.
Request Rule Mapping
Request Rule Configuration Options
Status Rule Mapping
Status Rule Configuration Options
Header Rule Mapping
SIP Header Rule Configuration Options
The Raw Rule
Normally used to change the SDP, the Raw Rule will change any regex match found within the entire SIP packet. If a Raw Rule was created to match on sip: and change it to sips:, then every sip: that appears in a packet would be changed to sips: using a single Raw Rule.
Raw Rule Performs a Straight Regex Replacement
Tokens
Tokens are basically variable names which have been pre-assigned to different portions of a SIP Message. Just like the numbers in an incoming SIP packet are mapped into Tranformation Table IEs (Called Number, Calling Number, etc.), various portions of a SIP Packet are mapped into SMM Tokens.
Tokens make it easier for you to know what's being changed. For instance, if you're making a SMM Rule to change the diversion number to be the same as the the calling number, you would use the SMM Rules menu to change the diversion value from the token from.user.userinfo.user (as that is the token that contains the calling number).
Tokens are Selected From Various SMM Configuration Items
Token Mapping
Below find a sample mapping of SIP messages sections to their corresponding tokens; x represents a SIP Request Line, Status Line or Header name. For example:
- The Display Name in a FROM header would be recorded in the from.displayname token.
The TO number would be recorded in the to.uri.userinfo.usertoken.
Tokens Mapped to Their Corresponding SIP Packet Elements
Some of the available tokens are listed below.
Request URI Header Tokens | Value |
|---|---|
request-line | sip:+15103644064@ux.vx.net;user=phone SIP/2.0 |
request-line.uri | sip:+15103644064@ux.vx.net |
request-line.uri.host | ux.vx.net |
request-line.uri.port | 5061 |
request-line.uri.userinfo.user | +15103644064 |
request-line.sipversion | 2.0 |
TO/FROM/P-headers Tokens | Value |
|---|---|
from | "Jane Doe"<sip:+14083483531:passwrd;usr=param:test@sba1.vx.net:5061;user=phone>;epid=03FE79405B;tag=d953c6165d |
from.displayname | "Jane Doe" |
from.param.tag | d953c6165d |
from.uri | sip:+14083483531@sba1.vx.net;user=phone |
from.uri.host | sba1.vx.net |
from.user.port | 5061 |
from.user.userinfo.password | passwrd |
from.user.userinfo.param.ext | 7565 |
from.user.userinfo.param.phone-context | cda.udp |
from.user.userinfo.user | +14083483531 |
Conditions
When you want an SMM to operate only if something specific occurs, then you create a Condition Rule. Condition Rules, which are applied with the Message Rule, can be configured to match specific numbers, tokens, or by regex.
Literal Condition Match
Token Condition Match
Regex Condition Match
More Information
The SMM feature cannot be used to create a SIP packet. As indicated above, the SMM feature handles a SIP packet either just before or just after the SIP Engine. In either case, an already-existing SIP packet is presented to the SMM function. The SMM function only works on packet it receives--it cannot create a packet.
Overview
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