-
1. Re: EIGRP Reliable Transport Protocol
Hi Paula
Maybe in RTP the T stands for transport.
This seems more detailed
http://www.rhyshaden.com/eigrp.htm
Regards Conwyn
-
2. Re: EIGRP Reliable Transport Protocol
Hi Paula,
EIGRP RTP isn't an extra protocol, it is more about how EIGRP neighbors exchange important packets. RTP is used in EIGRP for detecting packet loss and to ensure ordered delivery of the packets.
Jeremy Stretch wrote a good and short explanation about EIGRP RTP recently.
http://packetlife.net/blog/2009/jan/17/rtp-eigrp/
best regards,
jochen
-
3. Re: EIGRP Reliable Transport Protocol
Hi Jochen
I always thought a protocol was a defined as set of rules. So how packets are exchanged sounds like rules to me.
Hence RTP is a protocol. I do not think many protocols SNA, Netbios, Appletalk, IPX/SPX, BSC sit nicely on the OSI model.
Regards Conwyn
-
4. Re: EIGRP Reliable Transport Protocol
Thanks guys, some very useful links there.
This all really goes to confirm my initial feeling that EIGRP isnt exactly a layer 4 protocol at all and it is fair(er) to say that EIGRP RTP is the layer 4 protocol and EIGRP itself is almost an application, albeit one used by routers.
its all semantics I guess but when I see EIGRP as protocol 88 and no mention of RTP it makes me wonder what else im missing.
Paula
-
5. Re: EIGRP Reliable Transport Protocol
conwyn.flavell wrote:
Hi Jochen
I always thought a protocol was a defined as set of rules. So how packets are exchanged sounds like rules to me.
Hence RTP is a protocol. I do not think many protocols SNA, Netbios, Appletalk, IPX/SPX, BSC sit nicely on the OSI model.
Regards Conwyn
I totally agree with you. Maybe my explanation was a bit misleading. What I really wanted to say is that RTP isn't something, which has header fields, it's more like a set of rules.
-
6. Re: EIGRP Reliable Transport Protocol
Hi Paula
Remember EIGRP works on IP IPX and Appletalk all of which preceeded the OSI model.
Regards Conwyn
-
7. Re: EIGRP Reliable Transport Protocol
Hi Conwyn,
I may have skewed the thread a bit by comparing too directly to OSI.
What Im really trying to do is understand the stack for EIGRP and the layers that sit above Layer 3 whether IP or whatever.
As I understand it theres a layer , lets call it RTP and then another above that which is best described as EIGRP proper.
I know it seems to delve into the minutae of it all but im just trying to prepare for that question in the exam you know we all hate that seems to focus on just such minutae.
thanx,
Paula
-
8. Re: EIGRP Reliable Transport Protocol
Hi Paula
Could you imagine a world with EIGRP without RTP. Yes not EIGRP as we know it but a routing protocol which uses multicast or unicast to transfer routing information. So I think RTP is above layer 3 but if you compare it with Netbios/TCP perhaps it is at level 5. I open the debate.
Regards Conwyn
-
9. Re: EIGRP Reliable Transport Protocol
Of course this also begs the question, to add fuel to the fire:
Do EIGRP packets that are sent unreliably (Hellos and Acknowledgements) merely have the RTP layer absent ; assuming it is a separate encapsulation layer at all ??
Hmm, I think Im gonna have to get wireshark going in the office and see whats going on there.
Paula.
-
10. Re: EIGRP Reliable Transport Protocol
Actually, the header of an EIGRP packet looks like this:
Its clearly not an encapsulation but rather an option within the packet to be sent reliably (or otherwise) so I guess RTP is only an optional field within an EIGRP packet.
Of course, Im guessing??
Paula
-
11. Re: EIGRP Reliable Transport Protocol
Hi Paul
Here is the OSI model with friends
http://www.scribd.com/doc/2157432/OSI-Layers-Model-Network-Associates
BTW I posted this early if you scroll down the information is quite detailed.
http://www.rhyshaden.com/eigrp.htm
Regards Conwyn
-
12. Re: EIGRP Reliable Transport Protocol
IMO many things don't fit into OSI well because they simply doesn't have much to do with OSI... OSI is dead long ago
Some people like to use OSI for training purpose but they fail to realize the real world is simply not OSI....
Reliable Transport Protocol is more of Cisco's way saying their proprietary EIGRP protocol uses ACK....
If there isn't an RFC for it, it's not a protocol in my book....
-
13. Re: EIGRP Reliable Transport Protocol
sorry but i did not got which particular RFC you are searching?
-
