Joe,
I mocked up the following quick scenario:
<-------------Non Pim Enabled FastE Link------------->
R7
R8
<-----------------Pim Enabled Serial Link------------->
- OSPF enabled on both links and loopback 0
- FastE link is preferred
- R8 is RP/BSR router
- R7/R8 has igmp join on both loopback0 interfaces
In this configuration the routers are unable to ping each others mcast IP
addresses, which is correct behavior due to RPF issue
Added the following:
-MBGP (I) configuration between R7 & R8
-Set next-hop IP address for loopback to the Serial Link
In this configuration the RPF has been corrected. I'm able to ping mcast
interfaces from both routers.
Since this BGP configuration is iBGP and not eBGP this again leads me to
believe that the multicast BGP table is looked at first and then the unicast
table.
Configs are below:
***********R7**************
hostname R7
!
ip multicast-routing
!
interface Loopback0
ip address 7.7.7.7 255.255.255.255
ip pim sparse-mode
ip igmp join-group 225.0.0.7
!
interface Serial0/0
ip address 150.100.87.7 255.255.255.0
ip pim sparse-mode
encapsulation ppp
clock rate 2000000
!
!
interface FastEthernet2/0
ip address 150.100.78.7 255.255.255.0
speed 100
full-duplex
!
router ospf 1
log-adjacency-changes
network 7.7.7.7 0.0.0.0 area 0
network 150.100.78.7 0.0.0.0 area 0
network 150.100.87.7 0.0.0.0 area 0
!
router bgp 78
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 8.8.8.8 remote-as 78
neighbor 8.8.8.8 update-source Loopback0
!
address-family ipv4 multicast
neighbor 8.8.8.8 activate
neighbor 8.8.8.8 route-map MCAST in
no auto-summary
no synchronization
network 7.7.7.7 mask 255.255.255.255
exit-address-family
!
!
route-map MCAST permit 10
set ip next-hop 150.100.87.8
!
R7#show ip route
7.0.0.0/32 is subnetted, 1 subnets
C 7.7.7.7 is directly connected, Loopback0
8.0.0.0/32 is subnetted, 1 subnets
O 8.8.8.8 [110/2] via 150.100.78.8, 00:46:22, FastEthernet2/0
150.100.0.0/16 is variably subnetted, 7 subnets, 2 masks
O 150.100.108.0/24 [110/2] via 150.100.78.8, 00:46:22, FastEthernet2/0
C 150.100.87.0/24 is directly connected, Serial0/0
C 150.100.87.8/32 is directly connected, Serial0/0
C 150.100.78.0/24 is directly connected, FastEthernet2/0
!
R7#show ip bgp ipv4 multicast
BGP table version is 3, local router ID is 7.7.7.7
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 7.7.7.7/32 0.0.0.0 0 32768 i
*>i8.8.8.8/32 150.100.87.8 0 100 0 i
!
R7#show ip rpf 8.8.8.8
RPF information for ? (8.8.8.8)
RPF interface: Serial0/0
RPF neighbor: ? (150.100.87.8)
RPF route/mask: 8.8.8.8/32
RPF type: mbgp
RPF recursion count: 0
Doing distance-preferred lookups across tables
***********R8**************
!
hostname R8
!
ip multicast-routing
!
!
interface Loopback0
ip address 8.8.8.8 255.255.255.255
ip pim sparse-mode
!
interface FastEthernet0/0
ip address 150.100.78.8 255.255.255.0
speed 100
full-duplex
!
interface Serial0/0
ip address 150.100.87.8 255.255.255.0
ip pim sparse-mode
encapsulation ppp
ip igmp join-group 225.0.0.8
clock rate 2000000
!
!
router ospf 1
log-adjacency-changes
network 0.0.0.0 255.255.255.255 area 0
!
router bgp 78
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 7.7.7.7 remote-as 78
neighbor 7.7.7.7 update-source Loopback0
!
address-family ipv4 multicast
neighbor 7.7.7.7 activate
neighbor 7.7.7.7 route-map MCAST in
no auto-summary
no synchronization
network 8.8.8.8 mask 255.255.255.255
exit-address-family
!
ip pim bsr-candidate Loopback0 10
ip pim rp-candidate Loopback0
!
route-map MCAST permit 10
set ip next-hop 150.100.87.7
!
R8#show ip route
7.0.0.0/32 is subnetted, 1 subnets
O 7.7.7.7 [110/2] via 150.100.78.7, 00:53:22, FastEthernet0/0
8.0.0.0/32 is subnetted, 1 subnets
C 8.8.8.8 is directly connected, Loopback0
150.100.0.0/16 is variably subnetted, 4 subnets, 2 masks
C 150.100.87.7/32 is directly connected, Serial0/0
C 150.100.87.0/24 is directly connected, Serial0/0
C 150.100.78.0/24 is directly connected, FastEthernet0/0
!
R8#show ip rpf 7.7.7.7
RPF information for ? (7.7.7.7)
RPF interface: Serial0/0
RPF neighbor: ? (150.100.87.7)
RPF route/mask: 7.7.7.7/32
RPF type: mbgp
RPF recursion count: 0
Doing distance-preferred lookups across tables
On Apr 13, 2010, at 10:58 PM, Joe Astorino wrote:
> If it is eBGP you are fine. If it is iBGP the rpf will still prefer the
> unicast routing table. My suggestion is that you play with both while running
> "sh ip rpf"
>
>
> ------Original Message------
> From: Robert Simmons
> Sender: [email protected]
> To: CCIE OSL
> Subject: [OSL | CCIE_RS] Lab 5 Volume 3
> Sent: Apr 13, 2010 3:56 PM
>
> IPExperts,
>
> I was working on Troubleshooting Ticket No. 4 (Multicast in AS25) and I was
> able to make it work but, when I looked at the DSG I noticed that you guys
> added the "distance bgp 20 20 20" command to the multicast address family.
> The solution guide says this was done because RPF lookup is still dependent
> on AD but, I thought the way RPF worked was that it looked at the multicast
> BGP database first and then the unicast table. Since you are modifying the
> route's next-hop via MBGP route-map (pointing it to the sparse enabled
> interface) my thoughts are you wouldn't need to lower the MBGP AD.
>
> Am I missing something here?
>
> Thanks
>
> -Rob
> _______________________________________________
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>
>
> Sent from my Verizon Wireless BlackBerry
>
> Regards,
>
> Joe Astorino - CCIE #24347
> Sr. Technical Instructor - IPexpert
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