Multicast Redundancy

Unanswered Question
Apr 2nd, 2008

Hi All, we are deploying multicasting in my network over wan & LAN. now we are confused about multicast redundancy for same groups. We have a DR site which is replica of main site with same hardware & configuration. we have deployed sparse-dense mode with static RP. Its working fine but if the main site goes down multicast should work properly from DR site where we have same multicast source as main site with the same group IP.

Any help would be gr8.

NK

I have this problem too.
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cisco_lad2004 Wed, 04/02/2008 - 05:33

Hi

As long as you have a route to RP, you will converge. I am assuming you are sending from one source only.

RP needs to be redudant also, MSDP is a good option here.

HTH

PS: I have stayed away from talking about switch from shared tree to source tree assuming yoy wish to keep shared tree distribution.

Sam

jain.nitin Wed, 04/02/2008 - 09:33

thanks for your reply...I am using 3750 switch everywhere. & only one source group will be activated at the same time. Now we have two 3845 running at main site with HSRP. One of them acting as a multicast RP. There are two more routers on DR site with HSRP & there are clients also in the DR site, so when main site is live DR site clients will have stream from main site servers & if Main site goes down then every client will have stream from DR site sources...

how can I achieve this. I think MSDP heavily rely on BGP & MBGP which we dont have in our network.

Any other way we can achieve this. there are two more site across wan even crossing multiple ISPs..we are providing mcast over GRE tunnel...so for those clients also we have to take care of redundancy...

Thanks

NK

jain.nitin Sun, 04/06/2008 - 22:32

Hi, Thanks for your reply. I have gone thru the document for MSDP but still have feeling that for RPF check it requires bgp next-hope to configured & for bgp next-hope we need to configure BGP. Well I will try MSDP with mesh group & will check whether it works or not..

still want confirmation from you...if u hv implemented somewhere without BGP...

i m planning to put these commands on Routers which will act as RPs. by the way on 3750 switches where clients are connected wht would be the config... just pim sparse-dense mode or i will hv to configure MSDP here as well...

need your expert comment...

ip pim rp-address 10.100.1.4

ip msdp peer 10.100.1.2 connect-source lo0

ip msdp peer description 10.100.1.2 to RTR02

ip msdp peer 10.100.1.3 connect-source lo0

ip msdp peer description 10.100.1.3 to zRTR01

ip msdp peer 10.100.1.1 connect-source lo0

ip msdp peer description 10.100.1.1 to RTR01

ip msdp mesh-group xxX 10.100.1.2

ip msdp mesh-group xxX 10.100.1.3

ip msdp mesh-group xxX 10.100.1.1

Thanks

cisco_lad2004 Mon, 04/07/2008 - 03:12

I have configured MSDP based on IGP only (IS-IS in this case).

I have not used mesh groups, so kept at as simple as can be.

I recommend that if possible you make ur changes within a service window which would allow you to fine tune and test.

ip msdp peer x.x.x.x connect-source Loopback10 remote-as 65001

ip msdp description YYYYYY

ip msdp cache-sa-state

HTH

Sam

jain.nitin Tue, 04/08/2008 - 11:16

Hi, I tried msdp peer but it didnt work for me... I did not define any AS number in MSDP peer command as I mentioned in my earlier msg, i didnt use mesh group. I could see that peer relationship was up but I dont know why I was not able to see traffic at DR site while source was on main site & vice versa...one thing I want to tell u is that between DR & MAIN site I 6 switches & 4 routers on which ATM links are terminated so to avoid multicast confgiuration on these intermediate devices I have created a GRE tunnel between MAIN site HSRP routers & DR site routers..I m not sure weather MSDP creates problem with GRE tunnel or not ?

NW diagram is attached for your reference.

Attachment: 
jain.nitin Fri, 04/11/2008 - 22:17

Hi, I managed to get the MSDP peering UP & running between Primary Site router & DR site router over GRE. I can see msdp cache on DR site router & (*,G) & (S,G) entry on DR site router but still DR site client are not able to get multicast stream from Sources server which is in primary site. clients which are on primary site they r getting stream perfectly.. but I m not getting y clients in DR sites are not getting stream...when I say ip mroute on DR site client switch I only can see (*,G) entry not (S,G) entry...but on DR router which is directly connected on switch has both entry in it...I am attaching the config for both the routers & switch config where I am not getting

stream...also attaching the diagram of network..please help me to config ANYCAST so that I can achieve redundancy..

Thanks

Harold Ritter Sat, 04/12/2008 - 04:22

Jain,

RPF check fails for mcast packets received by DR client switch from DR primary router as the PIM neighbor is 10.200.3.11 (real address) and the route back to the source is via 10.200.3.9 (HSRP address). You would need to configure an mroute static route to fix this.

Regards,

jain.nitin Sat, 04/12/2008 - 04:42

Hi, Thanks for your reply...I tried to pur IP Mroute towards source & RP on the client switch & pointing it to 10.200.3.11 which is physical address of router interface connecting to client switch but still it was not working...anything else you see in log & configuration which I m missing..I m trying ANYCAST since 4 days but not working..please help me...

Thanks

Harold Ritter Sat, 04/12/2008 - 04:48

Jain,

Can you please elaborate on what you mean by it is not working. Did you do a "sh ip mroute" on the DR client switch to see whether the traffic is getting there? What do you use as a test stream?

Regards,

jain.nitin Sat, 04/12/2008 - 05:03

Dear Friend, what I was trying to tell that I m trying to implement ANYCAST but not getting success everytime MSDP peering comes UP but clients on DR site can not see multicast traffic...as per my earlier post I clearly mentioned that on the DR site router when I do sh ip mroute I can see both entries (*,G) & (S,G) but on client switch at dr site i can see only (*,G) entry not (S,G) entry..

I hope it clears your doubt...

Thanks

Harold Ritter Sat, 04/12/2008 - 05:12

Jain,

Can you please let us know what your test stream is (simple ping to the multicast address or real application). Also can you do a "show ip mroute", "show ip rpf " on the DR client switch.

Regards,

jain.nitin Sat, 04/12/2008 - 05:29

Hi, I told you that I have already attached the DR client switch config & output of Show Tech ipmulticast in my earlier post.. we are testing with a multicast client software which is used in real scenario by customer...its a unix based application.. show ip rpf command I can give you only tomorrow other than this I put what ever I can..

Thanks

Harold Ritter Sat, 04/12/2008 - 05:34

Jain,

I know you provided the information before but what I would like now is the output from the command I requested after you fixed the RPF issue on the DR client device.

Thanks,

cisco_lad2004 Sat, 04/12/2008 - 05:13

jain

u need to put asside MSDP and anycast and focus on troubleshooting basic Multicast forwarding.

1-on "sh ip mroute" do u see packets received and packets forwarded ?

2-sh ip rpf , whats the output.

3-do u have 2 RP with same IP address ?

Sam

jain.nitin Sat, 04/12/2008 - 05:22

If I dont configure MSDP it works with Static RP configuration from both end. Secondly I have attached the configuration & output of some commands in my earlier post this morning. In ANYCAST ofcourse we will have 2 RPs with same IPs..

Thanks

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