Nortel ISDN Signaling Link, Description, Installation And Operation

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ITG Engineering Guidelines Page 131 of 378
ITG Trunk 2.0 ISDN Signaling Link (ISL) Description, Installation and Operation
Note: When using separate subnets as recommended the Network
Activity LEDs provide valuable maintenance information for the
Ethernet voice interface. The single subnet configuration eliminates the
use of the Ethernet voice interface with its associated Network Activity
LEDs.
Subnet configurations
ITG 2.0 systems with only 8-port cards can configure both single and dual
subnets.
ITG 2.0 systems with both 8- and 24-port cards can have both single and dual
subnets. The dual subnet option is recommended. Single subnets are only
allowed if the E-LAN/T-LAN connection is on a 10BaseT hub or switch.
ITG 2.0 systems with only 24-port cards must configure a dual subnet.
The following restrictions apply:
• The Leader 0 and Leader 1 cards must co-reside on a single T-LAN with
the Node IP Address.
• Follower cards can reside on separate T-LANs.
• All ITG cards belonging to the same node must co-reside on the same
E-LAN.
Single subnet option for voice and management
Although not recommended, the "single subnet" option for voice and
management can be used where the combined voice and management traffic
on the E-LAN is so low that there is no impact on packetized voice QoS
performance, or the customer is willing to tolerate occasional voice quality
impairments caused by excessive management traffic, and there is no modem
router on the ITG E-LAN because remote support access is provided by
Remote Access Server (RAS) on the C-LAN or remote support access is not
required, and there is no firewall router between the E-LAN and the C-LAN.