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New Member

Multicast

QUES:

Configure R2 as the RP for the multicast group 227.7.7.7

R5 should be the RP for all other multicast groups.

ANS:

1. access-list 10 permit 227.7.7.7

2. access-list 11 deny 227.7.7.7

3.access-list 11 permit any

ip pim rp-address 10.1.2.2 10

ip pim rp-address 10.1.5.5 11

Note:

R2 ip address is 10.1.2.2

R5 ip address is 10.1.5.5

According to the above PIM question,since there is an exclusive deny at the end of all access-list (10) statement, is the second line of the access-list needed?

3 REPLIES
Cisco Employee

Re: Multicast

The second line is actually for ACL 11, not ACL 10.

The logic for ACL 11 is to first deny group 227.7.7.7, which is taken care of by R2 and then accept everything else.

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: Multicast

But since access-list is executed in branches,then group 227.7.7.7 would have been taken care of by access-list 10 and it wont get to the second statement....Is the second statement still neccessary ?

Hall of Fame Super Blue

Re: Multicast

As Harold has pointed out the deny statement is part of acl 11.

You are correct in what you say about lines within an access-list being executed in order but this doesn't apply to different access-lists ie. without the deny line at the start of acl 11 then R5 would become the RP for 277.7.7.7 as well.

Jon

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