Routing SIP and H.323 Calls Using Route Control Message

You are here: CSP Developer’s Guide: Internet Protocol > 8 Routing VoIP Calls > Routing SIP and H.323 Calls Using Route Control Message

This section explains routing VoIP calls that are controlled by SIP and H.323 where your host application uses the Route Control message to route the outbound side of the call. Using the Route Control message allows the host application to leverage Layer 4 Router functionality thereby relieving the host application from making the span/channel assignments on the IP Network Interface card modules.

The Router component (0x64) is a PPL state machine that references a database of resources (the Route Table) to route calls. It is separated from the call processing logic in the CSP. Refer to RTR Router (0x64) in the Developer’s Guide: Overview for PPL information including configuration bytes and general purpose registers.

A Route Table is a special type of PPL table (Type 3) containing only routing criteria data. The router accesses the table to obtain a destination address or criteria data type (0x08).

Route Table entries are arranged into route groups that include one criteria type.

A Resource Group table is a special type of PPL table (Type 4) containing only Resource Group data. When the Route Table entry data yields a specific Resource Group ID, the router accesses the table to obtain a destination address.

Resource groups include the span/channel and the IP address of the IP Network Interface card.

Use the following API messages to download the Route Tables and Resource Group tables to the CSP with a .cfg file:

The following diagram shows a call controlled by SIP signaling and identifies each step in the routing process. Each step is further explained after the diagram.

2. The SIP stack interfaces with the Router component to reserve the inbound channel.

3. The SIP User Agent Server sends the inbound call signal to the Inbound Span/Channel Layer 4 PPL components.

4. The Layer 4 PPL components send an inbound call trigger to the host application in the Request for Service with Data message. The inbound call is completed.

1. The host application sends the Route Control message to the Router component to hunt and seize the outbound resources.

2. The Router component sends an outbound seizure to the outbound span/channel Layer 4 PPL components.

3. The Layer 4 PPL components send the outbound call signal to the Layer 3 SIP User Agent Client.

4. The SIP User Agent Client initiates the outbound call using a SIP INVITE message.

This section provides examples of how the CSP routes a SIP or H.323 call including:

• An example of Route Tables and Resource Groups created using the Converged Services Administrator (CSA) and downloaded to the CSP with the PPL Download message. It is a simplified case in which the CSP has only one VDAC-ONE card with two VoIP modules.

• Detailed steps of how the Route Control message uses the Route Table and Resource groups. These steps refer to specific lines in the Route Table and Resource Group.

• Additional examples of Route Tables and Resource Groups that show the various configurations available. Annotations call out the Resource Groups and the Route Tables.

The following diagram shows, at a high level, how both inbound and outbound calls use Resources Groups. The information in this diagram corresponds to the information in the example that follows. That example contains the specific Route Tables and Resource Groups used to configure this scenario.

Following that is the Route Control message as well as the steps that the message completes to select the resources.

In the following example, two Resource Groups are set up to correspond to the two VoIP modules on the VDAC-ONE card. Annotations are included to make it easier to read.

The Route Control message uses two or more ICBs to make an outbound SIP or H.323 call. The Generic PPL ICB (0x001E) controls the span-channel and VoIP module selection through the Router component. Below is an example of a Route Control message. The first ICB, which is explained, could be used for a SIP or H.323 call.

The following steps explain how the Route Control message uses the Route Tables and Resource Groups to route a call.

1. The AIB (0x29) in the Route Control message directs the call to the Router component.

2. The Routing Method TLV (0x0013) specifies to use a criteria type. The Criteria Type TLV specifies the criteria to use to search for a route.

3. The Route Control message directs the Router component to search the Route Table for any resources that are mapped to physical VoIP channels (value - 0x0065 VoIP Physical).

4. The Router component finds Criteria Type 00 65 in Line 7 of the Route Table. Note that Lines 5 and 6 are not matched because they use different criteria types. There are two Terminating Resource Group TLVs (0x0015) in Line 7. The first contains the Resource Group ID 0001 and the second contains Resource Group ID 00002.

5. These IDs map to Resource Group IDs 00 01 and 00 02 respectively in Lines 2 and 3 of the Resource Group.

6. Line 2 maps VoIP Module IP Address 0a 0a 0a 02 to span 0000, channel 00 through span 0001, channel 07. Line 3 maps the VoIP Module IP Address 0a 0a 0a 04 to span 0001, channel 08 through span 0002, channel 0f.

7. The Router component routes the outbound call based on the VoIP module and Span/Channel.

00 21 00 d5 00 00 01 00 64 04 01 00 00 00 88 72 65 73 2f 67 72 6f 75 70 20 74 61 62 6c 65 00 00 00 00 00

00 2b 00 d6 00 00 01 00 64 04 01 00 01 00 01 00 01 00 01 00 0c 01 02 0d 03 00 00 00 0d 03 00 01 07 00 01 00 08 01 68 00 04 0a 0a 0a 02

00 2b 00 d6 00 00 01 00 64 04 01 00 02 00 01 00 01 00 01 00 0c 01 02 0d 03 00 01 08 0d 03 00 02 0f 00 01 00 08 01 68 00 04 0a 0a 0a 03

00 2b 00 d6 00 00 01 00 64 04 01 00 03 00 01 00 01 00 01 00 0c 01 02 0d 03 00 02 10 0d 03 00 03 17 00 01 00 08 01 68 00 04 0a 0a 0a 04

00 2b 00 d6 00 00 01 00 64 04 01 00 04 00 01 00 01 00 01 00 0c 01 02 0d 03 00 03 18 0d 03 00 04 1f 00 01 00 08 01 68 00 04 0a 0a 0a 05

00 21 00 d5 00 00 01 00 64 03 01 00 00 00 e7 72 6f 75 74 65 72 5f 74 61 62 6c 65 00 00 00 00 00 00 00 00

00 35 00 d6 00 00 01 00 64 03 01 00 01 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 02 ff ff ff ff 00 02 00 0d 00 15 00 02 00 01 00 63 00 03 01 00 01

00 35 00 d6 00 00 01 00 64 03 01 00 02 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 03 ff ff ff ff 00 02 00 0d 00 15 00 02 00 02 00 63 00 03 01 00 02

00 35 00 d6 00 00 01 00 64 03 01 00 03 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 04 ff ff ff ff 00 02 00 0d 00 15 00 02 00 03 00 63 00 03 01 00 03

00 35 00 d6 00 00 01 00 64 03 01 00 04 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 05 ff ff ff ff 00 02 00 0d 00 15 00 02 00 04 00 63 00 03 01 00 04

00 40 00 d6 00 00 01 00 64 03 01 00 05 c0 01 00 01 00 01 00 65 01 00 02 00 00 00 06 00 24 00 62 00 01 01 00 15 00 02 00 01 00 15 00 02 00 02 00 15 00 02 00 03 00 15 00 02 00 04 00 63 00 03 01 00 05

00 21 00 d5 00 00 01 00 64 04 01 00 00 00 1a 72 65 73 2f 67 72 6f 75 70 20 74 61 62 6c 65 00 00 00 00 00

00 23 00 d6 00 00 01 00 64 04 01 00 01 00 01 00 01 00 01 00 0c 01 02 0d 03 00 00 00 0d 03 00 1f 1f 00 00 00 00

00 21 00 d5 00 00 01 00 64 03 01 00 00 00 25 72 6f 75 74 65 72 5f 74 61 62 6c 65 00 00 00 00 00 00 00 00

00 2e 00 d6 00 00 01 00 64 03 01 00 02 c0 01 00 01 00 01 00 71 01 00 02 00 00 00 03 00 12 00 62 00 01 01 00 15 00 02 00 01 00 63 00 03 01 00 02

00 21 00 d5 00 00 01 00 64 04 01 00 00 01 10 72 65 73 2f 67 72 6f 75 70 20 74 61 62 6c 65 00 00 00 00 00

00 2b 00 d6 00 00 01 00 64 04 01 00 01 00 01 00 01 00 01 00 0c 01 02 0d 03 00 00 00 0d 03 00 01 07 00 01 00 08 01 68 00 04 0a 0a 0a 02

00 2b 00 d6 00 00 01 00 64 04 01 00 02 00 01 00 01 00 01 00 0c 01 02 0d 03 00 01 08 0d 03 00 02 0f 00 01 00 08 01 68 00 04 0a 0a 0a 03

00 2b 00 d6 00 00 01 00 64 04 01 00 03 00 01 00 01 00 01 00 0c 01 02 0d 03 00 02 10 0d 03 00 03 17 00 01 00 08 01 68 00 04 0a 0a 0a 04

00 2b 00 d6 00 00 01 00 64 04 01 00 04 00 01 00 01 00 01 00 0c 01 02 0d 03 00 03 18 0d 03 00 04 1f 00 01 00 08 01 68 00 04 0a 0a 0a 05

00 2b 00 d6 00 00 01 00 64 04 01 00 05 00 01 00 01 00 01 00 0c 01 02 0d 03 00 05 00 0d 03 00 06 07 00 01 00 08 01 68 00 04 0a 0a 0a 0b

00 2b 00 d6 00 00 01 00 64 04 01 00 06 00 01 00 01 00 01 00 0c 01 02 0d 03 00 06 08 0d 03 00 07 0f 00 01 00 08 01 68 00 04 0a 0a 0a 0c

00 2b 00 d6 00 00 01 00 64 04 01 00 07 00 01 00 01 00 01 00 0c 01 02 0d 03 00 07 10 0d 03 00 08 17 00 01 00 08 01 68 00 04 0a 0a 0a 0d

00 2b 00 d6 00 00 01 00 64 04 01 00 08 00 01 00 01 00 01 00 0c 01 02 0d 03 00 08 18 0d 03 00 09 1f 00 01 00 08 01 68 00 04 0a 0a 0a 0e

00 21 00 d5 00 00 01 00 64 03 01 00 00 01 af 72 6f 75 74 65 72 5f 74 61 62 6c 65 00 00 00 00 00 00 00 00

00 35 00 d6 00 00 01 00 64 03 01 00 01 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 02 ff ff ff ff 00 02 00 0d 00 15 00 02 00 01 00 63 00 03 01 00 01

00 35 00 d6 00 00 01 00 64 03 01 00 02 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 03 ff ff ff ff 00 02 00 0d 00 15 00 02 00 02 00 63 00 03 01 00 02

00 35 00 d6 00 00 01 00 64 03 01 00 03 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 04 ff ff ff ff 00 02 00 0d 00 15 00 02 00 03 00 63 00 03 01 00 03

00 35 00 d6 00 00 01 00 64 03 01 00 04 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 05 ff ff ff ff 00 02 00 0d 00 15 00 02 00 04 00 63 00 03 01 00 04

00 35 00 d6 00 00 01 00 64 03 01 00 05 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 0b ff ff ff ff 00 02 00 0d 00 15 00 02 00 05 00 63 00 03 01 00 05

00 35 00 d6 00 00 01 00 64 03 01 00 06 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 0c ff ff ff ff 00 02 00 0d 00 15 00 02 00 06 00 63 00 03 01 00 06

00 35 00 d6 00 00 01 00 64 03 01 00 07 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 0d ff ff ff ff 00 02 00 0d 00 15 00 02 00 07 00 63 00 03 01 00 07

00 35 00 d6 00 00 01 00 64 03 01 00 08 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 0e ff ff ff ff 00 02 00 0d 00 15 00 02 00 08 00 63 00 03 01 00 08

00 58 00 d6 00 00 01 00 64 03 01 00 09 c0 01 00 01 00 01 00 65 01 00 02 00 00 00 0a 00 3c 00 62 00 01 01 00 15 00 02 00 01 00 15 00 02 00 02 00 15 00 02 00 03 00 15 00 02 00 04 00 15 00 02 00 05 00 15 00 02 00 06 00 15 00 02 00 07 00 15 00 02 00 08 00 63 00 03 01 00 09

00 21 00 d5 00 00 01 00 64 04 01 00 00 00 44 72 65 73 2f 67 72 6f 75 70 20 74 61 62 6c 65 00 00 00 00 00

00 2b 00 d6 00 00 01 00 64 04 01 00 01 00 01 00 01 00 01 00 0c 01 02 0d 03 00 00 00 0d 03 00 07 1f 00 01 00 08 01 68 00 04 0a 0a 0a 02

00 2b 00 d6 00 00 01 00 64 04 01 00 02 00 01 00 01 00 01 00 0c 01 02 0d 03 00 08 00 0d 03 00 0f 1f 00 01 00 08 01 68 00 04 0a 0a 0a 03

00 21 00 d5 00 00 01 00 64 03 01 00 00 00 83 72 6f 75 74 65 72 5f 74 61 62 6c 65 00 00 00 00 00 00 00 00

00 35 00 d6 00 00 01 00 64 03 01 00 01 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 02 ff ff ff ff 00 02 00 0d 00 15 00 02 00 01 00 63 00 03 01 00 01

00 35 00 d6 00 00 01 00 64 03 01 00 02 c0 01 00 01 00 01 27 92 01 00 0e 01 00 00 00 00 00 0a 0a 0a 03 ff ff ff ff 00 02 00 0d 00 15 00 02 00 02 00 63 00 03 01 00 02

00 34 00 d6 00 00 01 00 64 03 01 00 03 c0 01 00 01 00 01 00 65 01 00 02 00 00 00 04 00 18 00 62 00 01 01 00 15 00 02 00 01 00 15 00 02 00 02 00 63 00 03 01 00 03

00 21 00 d5 00 00 01 00 64 04 01 00 00 00 34 72 65 73 2f 67 72 6f 75 70 20 74 61 62 6c 65 00 00 00 00 00

00 23 00 d6 00 00 01 00 64 04 01 00 01 00 01 00 01 00 01 00 0c 01 02 0d 03 00 00 00 0d 03 00 1f 1f 00 00 00 00

00 23 00 d6 00 00 01 00 64 04 01 00 02 00 01 00 01 00 01 00 0c 01 02 0d 03 00 32 00 0d 03 00 51 1f 00 00 00 00

00 21 00 d5 00 00 01 00 64 03 01 00 00 00 2b 72 6f 75 74 65 72 5f 74 61 62 6c 65 00 00 00 00 00 00 00 00

00 34 00 d6 00 00 01 00 64 03 01 00 02 c0 01 00 01 00 01 00 71 01 00 02 00 00 00 04 00 18 00 62 00 01 01 00 15 00 02 00 01 00 15 00 02 00 02 00 63 00 03 01 00 02

Voice over Internet Protocol. The delivery of voice information in digital form in discrete packets rather than in the traditional circuit-committed protocols of the public-switched telephone network (PSTN).

Session-Initiation Protocol. A signaling protocol used for establishing sessions in an IP network. A session could be a simple, two-way telephone call, or it could be a collaborative multi-media conference session.

ITU-T standard defines a set of call control, channel setup, and codec specifications for transmitting real-time voice and video over networks that do not offer guaranteed service or quality of service.

Call processing layer of the CSP.

Internet Protocol. Part of the TCP/IP family of protocols used to route messages and tracks the addresses of nodes.

See Programmable Protocol Language.

Protocol layer of the CSP.

Range of channels provided by T1 or E1 transmission service. A physical span is a group of channels taking up a single physical wire. A logical span is a group of channels taking up less than a single logical wire, or carried over more than one physical wire.

In SIP, an application program that sends SIP requests (See also Session Initiation Protocol). Clients may or may not interact directly with a person. Users agents and proxies contain clients (and servers).

CSA. GUI-based tool used to configure, provision and monitor a Excel platform related to, for example, SIP, H.323, and VDAC Resouce Attributes.

See Converged Services Administrator.

Voice Data Access Concentrator Card. Performs two-way conversion between circuit-switched data and packet-switched Ethernet data required by packetized voice applications such as VoIP.

See Information Control Block.

See Address Information Block.

Tag-Length-Value block. A standardized block that allows data to inserted in a standard way into API messages.

A 32-bit address, used in IP routing, which includes a Network address identifier assigned by a central authority and a Host ID (an end station identifier assigned by a LAN administrator).