You are here: CSP Developer’s Guide: Internet Protocol > 3 IP Network Interface Series 2 Card > General IP Attributes

General IP Attributes

Overview

The following are general IP resource attributes that apply to voice and fax connections:

IP Type Of Service

The IP Network Interface Series 2 card supports the IPv4 Type of Service field in the IP packet header. This field is used to instruct packet switches and routers in an IP-based network to control packets sent from a IP Network Interface Series 2 card. You can set options in this field to indicate that the packets should be given preferential treatment on a Class of Service basis.

Important! Most IP switches and routers do not currently support different levels of service.

You can configure the following IP Type of Service options for outgoing packets:

• Cost

• Reliability

• Throughput

• Delay

• Precedence

Default: 0x00 (No preferential options set)

Use TLV: 0x01D4 Type of Service

UDP Source Port Validation

If the User Datagram Protocol (UDP) Source Port Validation is enabled, the IP Network Interface Series 2 card verifies that the UDP source port of the incoming packets matches the destination port of the originating outgoing packets. If not, the packets will be transparently dropped.

Default: Enabled

Use TLV: 0x01DF Source Port Validate

Media Inactivity Detection (MID) Timer

The host can enable a Media Inactivity Detection (MID) Timer on a per channel basis to monitor the activity of the incoming media stream (for example, valid UDP packets).

When the MID Timer is enabled on a VoIP Channel, every valid UDP packet received on this channel refreshes the timer. If the timer expires and no valid packets have been received, a PPL Event Indication (0x0043) message is generated.

The host has the ability to configure two timeout values for the MID Timer, an Initial Media Inactivity (IMID) Timeout Value TLV (0x01EB) and a MID Timeout Value TLV (0x01EC). Both of these values are configured in units of 10 milliseconds.

When the channel is enabled, the MID Timer is loaded with the IMID Timeout Value. If the timer expires before the first valid packet is received, a PPL Event Indication (0x0043) message is generated with PPL Event 0x07, Received Initial Media Inactivity Timeout.

The receipt of a valid UDP packet causes the MID Timer to be reloaded with the MID Timeout Value. If a valid UDP packet is not received before the timer expires, a PPL Event Indication (0x0043) message is generated with PPL Event 0x08, Received Media Inactivity Timeout.

Important! In order to maintain backwards compatibility with the VDAC-ONE card’s implementation of the MID Timer, the timer is loaded initially with the MID Timeout Value when the IMID Timeout Value is disabled (0x0000). Under this circumstance, the MID Timer expiring results in a PPL Event Indication being generated with a PPL Event of 0x08, Received Media Inactivity Timeout.

Once the MID Timer has expired, the receipt of a valid UDP packet does NOT automatically re-enable the timer. The host must manually re-enable the timer by updating the active channel’s MID Timeout Value TLV (0x01EC). This is done using the Resource Attribute Configure (0x00E3) message. Upon receipt of this message, the IP Network Interface Series 2 card will re-enable the timer and load the supplied MID Timeout Value.

Important! If the host dynamically updates the MID Timeout Value while the MID Timer is enabled, the new value will not be loaded until after the next valid UDP packet is received.

Both the IMID and MID Timeout Values default to 0x0000, disabling the MID Timer. Enabling the IMID and disabling the MID cause the timer to automatically be disabled after the first packet is received. Enabling the MID and disabling the IMID causes the MID to be loaded initially.

Initial Media Inactivity Timeout (0x01EB) TLV

Used in:
Resource Attribute Configure message
Resource Attribute Query message
Route Control message
Outseize message

Byte | Description
0, 1 | Tag 0x01EB
2, 3 | Length 0x0004
4, 5 | Value[0, 1] 0x0000
6, 7 | Media Inactivity Detection Timeout (2 Bytes) 0x0000 - 0xFFFF (in 10 ms increments) 0x0000 is the default and indicates that the IMID detection is disabled. The Timer is loaded instead with the Media Inactivity Detection Timeout Value. Any other value causes the MID Timer to be initialized with this value.

Important! The IMID Timeout TLV cannot be dynamically updated on an active channel. The default IMID Timeout TLV can be configured on a per module basis.

Media Inactivity Detection Timer (0x01EC) TLV

Used in:
Resource Attribute Configure message
Resource Attribute Query message
Route Control message
Outseize message

Byte | Description
0, 1 | Tag 0x01EC
2, 3 | Length 0x0004
4, 5 | Value[0,1] 0x0000
6, 7 | RTP Initial Media Inactivity Timeout Value (2 Byte) 0x0000 - 0xFFFF (in 10 ms increments)) 0x0000 is the default and indicates that the MID Timer is disabled after the first packet is received.Setting both the IMID and MID to 0x0000 disables the MID Timer.

Important! The MID Timeout TLV can be dynamically updated on an active channel. The default MID Timeout TLV can be configured on a per module basis.

Examples of MID Timer Events

The examples below describe different MID Timer scenarios.

1. A call is started with an IMID Timeout of 0 and a MID Timeout of 5 seconds. The Timer is loaded with 5 seconds. The receipt of a valid packet reloads the timer with 5 seconds. If the timer ever expires, a MID Expired PPL Event of 0x08 is generated. (This example implies backwards compatibility with the VDAC-ONE card.)

2. A call is started with an IMID Timeout of 20 seconds and a MID Timeout of 5 seconds. The Timer is loaded with 20 seconds. If after 20 seconds, a valid packet is not received, an IMID Expired PPL Event of 0x07 is generated and the timer is disabled (for example a packet arriving at 21 seconds will not reload the timer). If a valid packet is received before 20 seconds, the timer is reloaded with 5 seconds. If 5 seconds expire, a MID Expired PPL Event of 0x08 is generated.

Important! Even though the MID Timeout is set for 5 seconds, the IMID Timeout overrides it, until the first packet is received.

3. A call is started with an IMID Timeout of 5 seconds and a MID Timeout of 20 seconds. The Timer is loaded with 5 seconds. If after 5 seconds, a valid packet is not received, an INIT MID Expired PPL Event of 0x07 is generated and the timer is disabled. If after 5 seconds, a valid packet is received, the timer is NOT reloaded. If a valid packet is received before 5 seconds, the timer is reloaded with 20 seconds. If 20 seconds expire, a MID Expired PPL Event of 0x08 is generated.

Important! Even though the MID Timeout is set for 20 seconds, the IMID Timeout overrides it until the first packet is received.

4. A call is started with an IMID Timeout of 0 seconds and a MID Timeout of 0 seconds. The Timer is disabled.

5. Call is starting with both timers set to 0 (disabled). During the call, the MID Timeout value is updated to 20 seconds. The timer is enabled and loaded with 20 seconds.

CNAME Support for VDAC/IPN-2

The CNAME field is supported for the IPN-2 and VDAC-ONE cards. The CNAME field will automatically be populated at channel configuration time and included in the RTCP Sender Report. The CNAME field is not configurable.

The data used for the CNAME field is comprised solely of the ASCII character formats for the VDAC/IP module’s source IP address (15 bytes) and source UDP (RTP) port number (5 bytes) for a specific RTP voice session, separated by an ASCII "colon" (":") character (1 byte).

You can use an Ethernet trace program to capture and analyze RTCP packets.

Internet Protocol. Part of the TCP/IP family of protocols used to route messages and tracks the addresses of nodes.
Tag-Length-Value block. A standardized block that allows data to inserted in a standard way into API messages.
The point in the Excel platform where a DS0 connects to a network. Also known as a "socket."
UPD. User Datagram Protocol. Unreliable networking layer that sits at the same level of networking stack as TCP. Part of the TCP/IP protocol suit, UDP is used for transferring IP datagrams between host computers, where each datagram is routed through the Internet based on the destination IP address.
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).
See Programmable Protocol Language.
A condition that, when met, drives a state machine from one state to another. A condition that drives a Component out of its current state by invoking an associated primitive.
Outgoing call setup during real-time call processing on a specific channel.
Real-Time Transport Protocol. Supports transport of real-time data like interactive voice and video over packet-switched networks.
Real-Time Transport Control Protocol.
American Standard Code for Information Interchange
The protocol used in most local area PC networks. Typically, most Ethernet networks support data transmission speeds up to 10 Mbps, but 100 Mbps is also possible.