Specifications

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Cisco IGX 8400 Series Provisioning Guide, Release 9.3.3 and Later Releases
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Chapter 4 Cisco IGX 8400 Series Trunks
Functional Overview
Virtual Trunks Supported on the IGX
Virtual trunks are not supported in mixed networks, and require switch software Release 9.2 or later. See
Table 4-5 for virtual trunk connections supported on the IGX.
Note The IGX supports a maximum of 15 virtual trunks per card, and a combined maximum of 32 logical
trunks (physical and virtual trunks) per node.
Each IGX node supports a combined maximum of 32 logical trunks (includes both physical and virtual
trunks) per node.
IMA on the IGX
IMA allows you to group physical T1 or E1 links to form a logical trunk with a higher data rate than a
single T1 or E1 trunk. IMA provides the following features:
• Use of the same configuration for all physical ports making up the logical IMA trunk
• Maintenance of retained links for the IMA trunks to prevent failures of the IMA trunk resulting from
failure of one of the physical ports
Note The IMA trunk does not fail unless the number of active ports falls below a user-specified
retained link threshold.
• Stable clock source or clock path using the first (lowest numbered) available physical line. If the
line fails, the next available line within the IMA trunk provides the clock source or clock path
• Full support for individual physical line alarms and statistics
IMA Feeder Nodes in an IGX Network
The IMA feeder node feature provides redundancy in case one of the physical lines on an IMA trunk
fails. This reduces the chance of a single point of failure when a single feeder trunk is out of service. In
addition, this feature allows you to configure the services on a feeder node instead of a routing node.
See Figure 4-2 for an example of an IGX IMA feeder node topology.
Table 4-5 Virtual Trunks Supported on the IGX
Chassis
Trunk
Endpoint Chassis
Trunk
Endpoint
IGX UXM IGX UXM
IGX UXM IGX UXM-E
IGX UXM BPX BXM
IGX UXM-E BPX BXM