In this section:

Use the SIP ARS Profile window to work with SIP Address Reachability Service (ARS) profiles used in determining when to blacklist a peer.

To achieve efficient device failover to a backup/secondary Application Server, the SBC uses ARS to determine if a server is reachable, providing the ability to temporarily "blacklist" a server IP address when specified criteria ar met. The ARS profile defines when to blacklist a peer and the recovery algorithm that defines when to remove blacklisting, restoring the peer into service. An ARS profile can be assigned to the services section of a SIP trunk group to trigger the blacklisting and recovery of any SIP peer(s) associated with the trunk group. Refer to Address Reachability Service for more information on using ARS and ARS profiles.

To View SIP ARS Profiles

On the SBC main screen, go to Configuration > Profile Management > Category: Service Profiles > SIP ARS Profile

 or


All > Profiles > Services > SIP ARS Profile

The SIP ARS Profile window is displayed.

Figure 1: SIP ARS Profile Window

To Create a SIP ARS Profile

To create a new SIP ARS Profile:

  1. Click New SIP ARS Profile. The Create New SIP ARS Profile window opens.

  2. Use the following table to configure the attributes for the new SIP ARS Profile and then click Save.

Table 1: SIP ARS Profile Parameters

Parameter

Description

Name

Specifies the name of the SIP ARS Profile.

Failure Response Codes

Use this parameter to define one or more response codes to treat as failure responses. Include one or more of the following values, separating each entry with a comma:

- 400-699 - list codes individually

- all – include all response codes from 400-699

- all4xx – include all 4xx response codes

- all5xx – include all 5xx response codes

- all6xx – include all 6xx response.


Note: Ensure Failure Response Codes values for a Path Check Profile and a SIP ARS Profile within the same zone/trunk group use similar values to avoid unexpected behavior. For example, it is not advisable to set the Path Check Profile Failure Response Codes to "all" and the SIP ARS Profile Failure Response Codes to "all4xx" and "all6xx"

Note: In the EMA UI, Failure Response Codes are configured as comma separated values. In the CLI, the values of the Failure Response Code are separated by spaces.

Blk List
Algorithms

Specifies the blacklisting algorithm to use for the ARS Profile. Any combination of algorithms can be specified for a profile. The options are:

  • noRetryAfer - use to trigger blacklisting when a peer endpoint sends SIP 503 responses without a Retry After header at a rate that exceeds a number defined by Blk List Alg No Retry After Num503 within the time interval defined by Blk List Alg No Retry After Duration.
  • retryafter - use to specify that when a message of the type specified by Blk List Alg Retry After Type is received with Retry-After field from a downstream server, this option puts that server into blacklist to prevent sending new call requests for the duration specified in the Retry-After header.
  • timeouts (default) - use the number of timeout responses to the specified SIP message type (Blk List Alg Timeouts Type) to trigger blacklisting the server. Blk List Alg Timeouts Type, Blk List Alg Timeouts Num Timeouts, and Blk List Alg Timeouts Duration must also be specified.

Blk List Alg
Timeouts Type

Specifies the message type to use in conjunction with the timeouts blacklisting algorithm:
• SIP -invite—use SIP INVITE messages as a timeout trigger.

Blk List Alg Rety After Methods.

Use this parameter to specify the SIP request types to retry after blacklist algorithm.

The options include:

  • sip-register 
  • sip-subscribe
  • sip-invite 
  • sip-notify 
  • sip-options

Blk List Alg
Timeouts Num Timeouts

Specifies the number of timeout events that must occur before blacklisting the address. Must be 1-3600; default value is 1.

Blk List Alg No Retry After Num503Specifies the number of SIP 503 responses without a Retry After header events sent by a peer to trigger blacklisting of that peer endpoint. The default is 1. The range allowed is 1 to 3600.
Blk List Alg No Retry After DurationSpecifies the duration, in seconds, in which the SIP 503 responses without a Retry After header events must occur to trigger blacklisting of the peer sending the responses. The default is 1. The range allowed is 1 to 3600.

Blk List Alg Timeouts Duration

Specifies the duration (in seconds) in which the specified number of timeouts should occur. Must be 1-3600. SIP-INVITE timeout is the only event that is currently supported.

Blk List Alg Retry After Type

Specifies the SIP status code which has a Retry After value:
• sip-503

Mid Dialog ARS Screen Level

Use this parameter to control when to apply ARS screening to a mid-dialog request.

  • Always - ARS is applied to all mid-dialog requests in a call.
  • Never (default) - ARS is not applied to mid-dialog requests.
  • Only If Not Black List Due to 503 - ARS is applied to mid-dialog requests unless blacklisting due to 503 is encountered.

Recovery
Algorithm

Specifies the type of recovery algorithm used after an IP address has been blacklisted:
• Probe (default) - the ARS initiates an active "ping" to the blacklisted server until it gets a response. Once a response is received, the address is removed from the blacklist. The Probe Method, Probe Interval, Probe Num Responses, and Probe Duration attributes for the recovery algorithm must also be specified.
• Timer - the ARS removes the entry for the blacklist after the configured Timer Duration.

Recovery Alg
Timer Duration

Specifies the duration (in seconds), for which the IP address will remain blacklisted when Timer is the recovery algorithm. Must be 1-3600.

Recovery Alg
Probe Method

Specifies the Probe recovery algorithm (ping) method for blacklist recovery:
• SIP -options—use a SIP OPTIONS request

Recovery Alg
Probe Interval

Specifies the probe Probe recovery algorithm interval (in seconds) for blacklist recovery. Must be 1 - 600 (default is 1).

Recovery Alg Probe Num Responses

Specifies the number of consecutive responses that must occur before removing an entry from the blacklist when Probe is the recovery algorithm. Must be 1 - 32 (default is 1).

Recovery Alg
Probe Duration

Specifies the Probe recovery algorithm duration (in seconds) during which the specified number of probe responses should occur. Must be 1-3600 (default is 1).

Recovery Alg for Timeouts

Specifies the type of recovery algorithm for the endpoints blacklisted with timeouts algorithm.

  • none - use the recovery algorithm specified in the ARS profile.
  • probe - use probe as recovery algorithm for the endpoints blacklisted with timeouts algorithm.
  • timer - use timer as the recovery algorithm for the endpoints blacklisted with timeouts algorithm.

Note: When the flag is set to none, the SBC continues with the default behavior which is specified in the recoveryAlgorithm flag.

Recovery Alg for No Retry After

Specifies the type of recovery algorithm for the endpoints blacklisted with 503 noRetryAfter algorithm.

  • none - use the recovery algorithm specified in the ARS profile.
  • probe - use probe as the recovery algorithm for the endpoints blacklisted with 503 noRetryAfter algorithm.
  • timer - use timer as the recovery algorithm for the endpoints blacklisted with 503 noRetryAfter algorithm.

Note: When the flag is set to none, the SBC continues with the default behavior specified in the recoveryAlgorithm flag.



Note

Ribbon recommends to not configure Path Check Profile and SIP ARS Profile on the same peer to avoid unexpected results. As a general rule, the Path Check Profile is configured on the access leg where there is less traffic, and the ARS Profile is configured on the peer leg where there is continuous traffic. 


To Edit a SIP ARS Profile

To edit a SIP ARS Profile:

  1. Click the radio button next to the name of the SIP ARS Profile you want to edit. The Edit Selected SIP ARS Profile window opens.

  2. Make the required changes and click Save.

To Copy a SIP ARS Profile

To copy a SIP ARS Profile and make changes to the copy:

  1. Click the radio button next to the name of the SIP ARS Profile you want to copy.

  2. Click Copy SIP ARS Profile. The Copy Selected SIP ARS Profile window opens.
  3. Make the required changes and click Save.

To Delete a SIP ARS Profile

To delete a SIP ARS Profile:

  1. Click the radio button next to the name of the SIP ARS Profile you want to delete.
  2. Click the delete icon (X) at the end of the row.
  3. Confirm the deletion when prompted.


noRetryAfer - use to trigger blacklisting when a peer endpoint sends SIP 503 responses without a Retry After header at a rate that exceeds a number defined by Blk List Alg No Retry After Num503 within the time interval defined by Blk List Alg No Retry After Duration.