3com S7906E 설치 설명서

 

1-14 

Enter system view 

— 

Enter public instance MSDP view 
or VPN instance MSDP view 

msdp [ vpn-instance 
vpn-instance-name ] 

— 

Enable the device to send SA 
request messages  

peer peer-address 
request-sa-enable 

Optional 

Disabled by default 

Configure a filtering rule for SA 
request messages  

peer peer-address 
sa-request-policy [ acl 
acl-number ] 

Optional 

SA request messages are 
not filtered by default  

 

Before you can enable the device to send SA requests, be sure to disable the SA message cache 

mechanism.  

 

By configuring an SA message creation rule, you can enable the router to filter the (S, G) entries to be 

advertised when creating an SA message, so that the propagation of messages of multicast sources is 

controlled.  

By configuring a filtering rule for receiving or forwarding SA messages, you can enable the router to filter 

the (S, G) forwarding entries to be advertised when receiving or forwarding an SA message, so that the 

propagation of multicast source information is controlled at SA message reception or forwarding.  

By configuring a TTL threshold for multicast data packet encapsulation in SA messages, you can control 

the multicast data packet encapsulation in SA messages and limit the propagation range of SA 

messages:  

z 

Before creating an SA message with an encapsulated multicast data packet, the router checks the 

TTL value of the multicast data packet. If the TTL value is less than the threshold, the router does 

not create an SA message; if the TTL value is greater than or equal to the threshold, the router 

encapsulates the multicast data in an SA message and sends the SA message out.  

z 

Upon receiving an SA message with an encapsulated multicast data packet, the router decrements 

the TTL value of the multicast packet by 1 and then checks the TTL value. If the TTL value is less 

than the threshold, the router does not forward the SA message to the designated MSDP peer; if 

the TTL value is greater than or equal to the threshold, the router re-encapsulates the multicast 

data in an SA message and sends the SA message out.