After ports are preprovisioned, multilink bundles (MLPPP) or IMA groups can be configured to increase the bandwidth available between two nodes.
The following cards, modules, and platforms support multilink bundles:
16-port T1/E1 ASAP Adapter card
32-port T1/E1 ASAP Adapter card
2-port OC3/STM1 Channelized Adapter card
4-port OC3/STM1 / 1-port OC12/STM4 Adapter card
T1/E1 ports on the 4-port T1/E1 and RS-232 Combination module (on 7705 SAR-H)
T1/E1 ports on the 7705 SAR-A
T1/E1 ports on the 7705 SAR-M
T1/E1 ports on the 7705 SAR-X
The following cards, modules, and platforms support IMA groups:
2-port OC3/STM1 Channelized Adapter card
16-port T1/E1 ASAP Adapter card
32-port T1/E1 ASAP Adapter card
T1/E1 ports on the 7705 SAR-M
All physical links or channels in a bundle or group combine to form one logical connection. A bundle or group also provides redundancy in case one or more links that participate in the bundle fail. For command syntax, see Configuring Multilink PPP Bundles. To configure channelized ports for TDM, see Configuring Channelized Ports.
For 12-port Serial Data Interface cards and the RS-232 ports on the 4-port T1/E1 and RS-232 Combination module, some or all of a port bandwidth can be dedicated to a channel by aggregating a number of DS0s into a single bundle. Serial data transmission rates below the rate of a single DS0, that is, less than 64 kb/s, are achieved using the High Capacity Multiplexing (HCM) proprietary protocol. These rates are known as subrates, and are supported only when operating in RS-232 mode or X.21 mode.
A DS0 channel operating at a rate less than 64 kb/s still uses a full 64 kb/s timeslot.