3com S7906E インストール手順

 

1-15 

Follow these steps to configure a filtering rule for receiving or forwarding SA messages:  

Enter 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  

 

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:  

Enter system view 

— 

Enter public instance MSDP view or 
VPN instance MSDP view 

msdp [ vpn-instance 
vpn-instance-name ] 

— 

Enable the SA cache mechanism  

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