Manual Chapter : About managing MRF SIP session traffic

Applies To:

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BIG-IP LTM

  • 14.0.1, 14.0.0, 13.1.5, 13.1.4, 13.1.3, 13.1.1, 13.1.0
Manual Chapter

Through the SIP Session Profile, you can use Message Routing Framework (MRF) to manage SIP traffic across pool members by means of configuring and using Via headers. When you configure Via headers to manage SIP traffic, dependencies between settings apply, enabling you to steer traffic and control requests and responses, as necessary.

Note: When a client Via header only specifies an address, without specifying a port, the BIG-IP® system uses default port 5060. For example, if a client sends a request with Via header SIP/2.0/TCP 192.168.20.1, in SIP session traffic scenario 1 (default), the BIG-IP system sends a response to the client with Via header SIP/2.0/TCP 192.168.20.1/5060.

Example: SIP session traffic scenario 1 (default)

In SIP session traffic scenario 1 (default), the BIG-IP system receives a request with a Via1 header from a client, and inserts a Via2 header into the request before forwarding the request to the server. When the server provides a response, the BIG-IP system removes the Via2 header from the response, before forwarding the response to the client. If the originating connection no longer exists, the Via2 header that BIG-IP system inserted is no longer available; consequently, the BIG-IP system uses the Via1 header, forwarding the message to the client IP address and port specified by that Via header.

An example of SIP session traffic scenario 1

An example of SIP session traffic scenario 1 (default)

When configuring this scenario, the following SIP Session Profile settings apply.

SIP Session Profile control Setting or value
Honor Via Enabled
Do Not Connect Back Disabled
Insert Via Header Enabled
Custom Via Not applicable

Example: SIP session traffic scenario 2

In SIP session traffic scenario 2, the BIG-IP system receives a request with a Via1 header from a client, and inserts a Via2 header into the request before forwarding the request to the server. When the server provides a response, the BIG-IP system removes the Via2 header from the response, before forwarding the response to the client. When the originating connection no longer exists, then the BIG-IP system drops the response message and increments the statistic for Messages failed due to connection dropped.

An example of SIP session traffic scenario 2

An example of SIP session traffic scenario 2

When configuring this scenario, the following SIP Session Profile settings apply.

SIP Session Profile control Setting or value
Honor Via Enabled
Do Not Connect Back Enabled
Insert Via Header Enabled
Custom Via Not applicable

Example: SIP session traffic scenario 3

In SIP session traffic scenario 3, the BIG-IP system receives a request with a Via1 header from a client, and inserts a Via2 header into the request before forwarding the request to the server. When the server provides a response, the BIG-IP system removes the Via2 header from the response, before forwarding the response to the client. If the originating connection no longer exists, then the Via header that BIG-IP system inserted is no longer available; consequently, the BIG-IP system uses the next available Via header, but, because the Honor Via setting is Disabled, the BIG-IP system does not forward the message to the client IP address and port specified by that Via header.

An example of SIP session traffic scenario 3

An example of SIP session traffic scenario 3

When configuring this scenario, the following SIP Session Profile settings apply.

SIP Session Profile control Setting or value
Honor Via Disabled
Do Not Connect Back Disabled
Insert Via Header Enabled
Custom Via Not applicable

Example: SIP session traffic scenario 4

In SIP session traffic scenario 4, the BIG-IP system receives a request with a Via1 header from a client, and inserts a Via2 header into the request before forwarding the request to the server. When the server provides a response, the response from the BIG-IP to the client must be managed by means of an iRule, for example, MR::message nexthop TMM:flow_id or MR::message route virtual vs_name host ip:port.

An example of SIP session traffic scenario 4

An example of SIP session traffic scenario 4

When configuring this scenario, the following SIP Session Profile settings apply.

SIP Session Profile control Setting or value
Honor Via Not applicable
Do Not Connect Back Not applicable
Insert Via Header Enabled
Custom Via Custom Via header value, for example: SIP/2.0/TCP www.siterequest.com:4343 or SIP/2.0/SCTP 10.10.4.32

Example: SIP session traffic scenario 5

In SIP session traffic scenario 5, the BIG-IP system receives a request with a Via1 header from a client, but does not insert a Via header into the request before forwarding the request to the server. When the server provides a response, the BIG-IP system uses the client Via1 header in the response to forward the message to the client IP address and port specified by that Via header.

An example of SIP session traffic scenario 5

An example of SIP session traffic scenario 5

When configuring this scenario, the following SIP Session Profile settings apply.

SIP Session Profile control Setting or value
Honor Via Enabled
Do Not Connect Back Not applicable
Insert Via Header Disabled
Custom Via Not applicable

Example: SIP session traffic scenario 6

In SIP session traffic scenario 6, the BIG-IP system receives a request with a Via1 header from a client, but does not insert a Via header into the request before forwarding the request to the server. Instead, the BIG-IP system uses the Via1 header specified in the request. When the server provides a response, the BIG-IP system uses the Via1 header in the response, but does not forward the message to the client IP address and port specified by that Via header.

An example of SIP session traffic scenario 6

An example of SIP session traffic scenario 6

When configuring this scenario, the following SIP Session Profile settings apply.

SIP Session Profile control Setting or value
Honor Via Disabled
Do Not Connect Back Not applicable
Insert Via Header Disabled
Custom Via Not applicable