3Com S7906E - Switch, Configuration Manual

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1-15
Follow these steps to configure a filtering rule for receiving or forwarding SA messages:
To do... Use the command... Remarks
Enter system view system-view —
Enter public instance MSDP
view or VPN instance MSDP
view
msdp [ vpn-instance
vpn-instance-name ]
—
Configure an SA message
creation rule import-source [ acl
acl-number ]
Required
No restrictions on (S, G) entries
by default
Configure a filtering rule for
receiving or forwarding SA
messages peer peer-address sa-policy
{ import | export } [ acl
acl-number ]
Required
No filtering rule by default
Configure the TTL threshold for
multicast data packet
encapsulation in SA messages
peer peer-address
minimum-ttl ttl-value
Optional
0 by default
Configuring the SA Cache Mechanism
To reduce the time spent in obtaining the multicast information, you can enable the SA cache
mechanism to cache (S, G) entries contained in SA messages locally on the router. However, the more
(S, G) entries are cached, the larger memory space of the router is used.
With the SA cache mechanism enabled, when receiving a new (*, G) join message, the router searches
its SA cache first:
z
If the corresponding (S, G) entry does not exist in the cache, the router waits for the SA message its
MSDP peer will send in the next cycle;
z
If the corresponding (S, G) entry exists in the cache, the router joins the corresponding SPT rooted
at S.
To protect the router effectively against denial of service (DoS) attacks, you can set a limit on the
number of (S, G) entries the router can cache.
Follow these steps to configure the SA message cache:
To do... Use the command... Remarks
Enter system view system-view —
Enter public instance MSDP view or
VPN instance MSDP view msdp [ vpn-instance
vpn-instance-name ]
—
Enable the SA cache mechanism cache-sa-enable
Optional
Enabled by default
Configure the maximum number of (S,
G) entries learned from the specified
MSDP peer that the router can cache
peer peer-address
sa-cache-maximum
sa-limit
Optional
8192 by default