Aaaaaand it's official: I've forgotten *everything* related multicast since my pass :-(
They always say you're not half-pregnant with multicast -- you either work with it every day, or never. I'm in the "never" camp... Bob -- Sent from my iPhone, please excuse any typos. > On Jan 7, 2014, at 6:01 PM, Tony Singh <[email protected]> wrote: > > > MSDP and MBGP (multicast BGP) are independent of each other but required for > inter-domain multicast, MSDP enables PIM-SM domain RP's to share source > information via sa-cache messages (S,G) via a TCP connection to each other, > the cases where you wouldn't use MBGP with MSDP would be an anycast > implementation via some IGP domains > > MSDP control-plane RPF checks are ignored if we have just two peers, if we > have more then two peers then the originator-id is checked to ensure its own > RP address is not originating the message in which case it would fail (if no > originator-id is selected then preference is given to the loopbacks) > > If you get a question where a restriction of not changing IGP AD/metric or > static mroute is imposed and IF the topology permits it then create a MBGP > peer to originate the source of the multicast feed and also the RP address, > this way you can route around the RPF failure. > > Order of preference for RPF checks are as follows: > > Static mroutes > DVMRP routes > MBGP routes > Unicast routes > > So as you can see MBGP routes are preferred for RPF over unicast, you still > need to ensure PIM is enabled on the relevant data-planes for this to work! > > -- > BR > > Tony > > Sent from my iPad > >> On 7 Jan 2014, at 20:08, "Ryanlk18 ." <[email protected]> wrote: >> >> You can use MPBGP multicast address-family to carry source information >> across the network to the RP. This can be useful in dealing with RPF >> issues where static mroutes won't work or you cannot manipulate the >> underlying routing protocol. >> >> MSDP is used to connect RPs together across multicast domains. This is >> needed when you have multiple multicast domains that need to be connected >> in order to share multicast feeds across the network. >> >> It could be possible to peer MSDP through a GRE Tunnel, but I've always >> used MSDP and MPBGP together as they are both necessary to carry the source >> and RP information to bridge the domains. >> >> V/r, >> >> Ryan Krcelic >> >> >> >>> On Tue, Jan 7, 2014 at 2:31 PM, Andrew LaPorte <[email protected]> wrote: >>> >>> I'm going to try to help out here a bit. >>> >>> BGP and MSDP are not directly related to one another. You can have MSDP >>> without having BGP but it is typical to have BGP and Multicast as that is a >>> larger environment. >>> >>> MSDP simply allows one RP to exchange multicast information with another >>> RP, >>> i.e. source A can register with RP A then another source B can register >>> with >>> RP B. If RP A and RP B have MSDP between them then both with know about >>> source A and source B. >>> >>> Now if you want a client to be able to get to both source A and source B >>> they must have a route that passes an RFP check. This is where BGP or OSPF >>> or EIGRP would come in typically. >>> >>> Hope this helps. >>> >>> AndyL >>> >>> >>> -----Original Message----- >>> From: [email protected] >>> [mailto:[email protected]] On Behalf Of Ryan Jensen >>> Sent: Tuesday, January 7, 2014 1:47 PM >>> To: [email protected] >>> Subject: [OSL | CCIE_RS] Multicast question >>> >>> I all, this is probably an amateur question, but I'm having an issue >>> wrapping my head around how BGP for multicast relates to MSDP. >>> Here's how I Think they relate: >>> BGP for multicast shares routes to RPs for the purpose of RPF MSDP shares >>> 'routes' to multicast sources. >>> >>> The sources that are shared via MSDP need to be reachable via the routes >>> learned from BGP yes? >>> >>> Is this a correct understanding? >>> _______________________________________________ >>> Free CCIE R&S, Collaboration, Data Center, Wireless & Security Videos :: >>> >>> iPexpert on YouTube: www.youtube.com/ipexpertinc >>> >>> _______________________________________________ >>> Free CCIE R&S, Collaboration, Data Center, Wireless & Security Videos :: >>> >>> iPexpert on YouTube: www.youtube.com/ipexpertinc >> _______________________________________________ >> Free CCIE R&S, Collaboration, Data Center, Wireless & Security Videos :: >> >> iPexpert on YouTube: www.youtube.com/ipexpertinc > _______________________________________________ > Free CCIE R&S, Collaboration, Data Center, Wireless & Security Videos :: > > iPexpert on YouTube: www.youtube.com/ipexpertinc _______________________________________________ Free CCIE R&S, Collaboration, Data Center, Wireless & Security Videos :: iPexpert on YouTube: www.youtube.com/ipexpertinc
