3Com S7906E Command Reference Manual page 1286

Parameters
None
Description
Use the summary automatic command to enable automatic summarization for redistributed subnets.
Use the undo summary automatic command to disable automatic summarization.
By default, automatic summarization is disabled.
Note that:
The default routes and the routes imported with the network command cannot be automatically
summarized.
The summary automatic command helps IPv4 MBGP limit the number of routes redistributed
from IGP.
Examples
# In IPv4 MBGP address family view, enable automatic route summarization.
<Sysname> system-view
[Sysname]bgp 100
[Sysname-bgp] ipv4-family multicast
[Sysname-bgp-af-mul] summary automatic
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