I've always described it like this: They are application layer protocols that provide services to the network layer.
We all know routing happens at the network layer (ie routing table lookup, forwarding etc). How the routing table gets populated does not necessarily need to have anything to do with the network layer at all. Think of static routes? What layer of the OSI model puts those in the routing table? Layer 8? Cheers, Matt CCIE #22386 CCSI #31207 2009/8/19 Taqdir Singh <[email protected]>: > TCP and UDP are transport layer protocols. RIP uses UDP and BGP uses TCP.. > > Please clear more how RIP and BGP are application layer ? > > Sincerely, > Taqdir Singh > 91-9911709496 > Do today what others won't So you can live tomorrow what others can't > > ________________________________ > From: Rick Mur <[email protected]> > To: Taqdir Singh <[email protected]> > Cc: prakash patel <[email protected]>; [email protected] > Sent: Wednesday, 19 August, 2009 1:49:38 AM > Subject: Re: [OSL | CCIE_RS] RIP and BGP are application layer protocol > > BGP is an application layer protocol since it uses TCP for communicating > with neighbors. > Other protocols like OSPF and EIGRP use their own IP protocol number and are > not relying on TCP or UDP. > Why BGP is not changing the next-hop while advertising in iBGP is definitely > a design decision. Which is an answer to your Why :-) > The reason behind is that you are letting the underlying IGP choose which > path to take to the BGP next-hop. Then it depends on your IGP set-up how the > traffic gets through the network. Of course there are a lot of ways to > overcome this, but you really need to ask yourself if you want to that. If > you don't want to or are not allowed to advertise the link connecting to the > eBGP neighbor to be advertised in your network, then you have no other > option that to issue a next-hop-self for example. > Read RFC 1771 (http://www.ietf.org/rfc/rfc1771.txt) for more exact > explanations. > > -- > Regards, > > Rick Mur > CCIE2 #21946 (R&S / Service Provider) > Juniper JNCIA-ER & JNCIA-EX > MCSA:Messaging, MCSE > Sr. Support Engineer – IPexpert, Inc. > URL: http://www.IPexpert.com > On 18 aug 2009, at 16:14, Taqdir Singh wrote: > > Hi Prakash > > I know we can use next hop self . but that is not answer to my question.. > > my question....is why BGP is so made to carry next hop of ebgp in internal > AS ? > > AS100(C)----e-bgp---AS200(A)----ibgp----AS200(B) > > Why BGP was not made so that router A automatically advertise routes to B > with next hop of itself.. as in case of all the other routing protocols ? > > and Why BGP is application layer ? > > Sincerely, > Taqdir Singh > 91-9911709496 > Do today what others won't So you can live tomorrow what others can't > > ________________________________ > From: prakash patel <[email protected]> > To: [email protected]; [email protected] > Sent: Tuesday, 18 August, 2009 7:31:20 PM > Subject: RE: [OSL | CCIE_RS] RIP and BGP are application layer protocol > > RIP is the oldest one where some hosts can learn RIP routes from router. ON > host, RIP has to run as application ..am I right? > > BGP can change by doing "next-hop-self" so you have that option. > > > > ________________________________ > Date: Tue, 18 Aug 2009 19:20:16 +0530 > From: [email protected] > To: [email protected] > Subject: [OSL | CCIE_RS] RIP and BGP are application layer protocol > > Can any1 please clear , how RIP and BGP are application layer protocols ? > Why BGP is so made to carry the E-BGP next-hop in internal AS ? > > Sincerely, > Taqdir Singh > 91-9911709496 > Do today what others won't So you can live tomorrow what others can't > ________________________________ > Love Cricket? Check out live scores, photos, video highlights and > more. Click here. > ________________________________ > Get back to school stuff for them and cashback for you. Try BingT now. > ________________________________ > See the Web's breaking stories, chosen by people like you. Check out Yahoo! > Buzz._______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > > ________________________________ > Looking for local information? Find it on Yahoo! Local > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
