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EIGRP Packet question
OK here is the play
router 1 losses if seccessor route and has no feasible seccessor.
It sends out a "Query" packet.
Router 2 find a new route and send a "Reply" packet back to router 1.
Now does the "Reply" packet contain the new route? or does router 2 send both a "Reply" and "Update" packet?
Exactly how will router 1 get the new route from router 2?
Thanks.
router 1 losses if seccessor route and has no feasible seccessor.
It sends out a "Query" packet.
Router 2 find a new route and send a "Reply" packet back to router 1.
Now does the "Reply" packet contain the new route? or does router 2 send both a "Reply" and "Update" packet?
Exactly how will router 1 get the new route from router 2?
Thanks.
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networker050184
Mod Posts: 11,962 Mod
Good question that I didn't really know the answer too so I labbed it up. It looks like the router that responds with the new path information only sends back the Reply and no Update.An expert is a man who has made all the mistakes which can be made. -
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Dilbert65
Member Posts: 73 ■■□□□□□□□□
So then how does router 1 get the new route? I tried on my lab as well and got stumped. -
Optionsnetworker050184
Mod Posts: 11,962 Mod
The information is in the Reply. Check out this Wireshark capture I took out the lab.
Cisco HDLC Internet Protocol, Src: 10.12.12.2 (10.12.12.2), Dst: 10.12.12.1 (10.12.12.1) Cisco EIGRP Version = 2 Opcode = 4 (Reply) Checksum = 0xa60f Flags = 0x00000000 Sequence = 105 Acknowledge = 55 Autonomous System : 1 IP internal route = 10.23.23.0/24 Type = 0x0102 (IP internal route) Size = 28 bytes Next Hop = 0.0.0.0 Delay = 256000 Bandwidth = 25600 MTU = 1500 Hop Count = 0 Reliability = 255 Load = 1 Reserved Prefix Length = 24 Destination = 10.23.23.0
EDIT: Got to love that dynamips serial interface capture! Best way to learn is to check out what the routers are actually sending to each other IMO.An expert is a man who has made all the mistakes which can be made. -
OptionsDilbert65
Member Posts: 73 ■■□□□□□□□□
Thank you very much. That is exactly what I was looking for. Guess I will have to install wireshark for my lab rack in case I run into some other odd ball questions.
Do you have your wireshark hooked into your switch and are you mirroring the port somehow? What I mean is how are you able to get in the middle of the 2 routers to capture that infomation? -
Optionsnetworker050184
Mod Posts: 11,962 Mod
Thank you very much. That is exactly what I was looking for. Guess I will have to install wireshark for my lab rack in case I run into some other odd ball questions.
Do you have your wireshark hooked into your switch and are you mirroring the port somehow? What I mean is how are you able to get in the middle of the 2 routers to capture that infomation?
Dynamips can do an inline capture. Its pretty sweet. I'd recommend you check it out if you haven't already. This was actually over a serial link also if you notice the "Cisco HDLC" encapsulation.An expert is a man who has made all the mistakes which can be made. -
OptionsDilbert65
Member Posts: 73 ■■□□□□□□□□
figures I have real equipment. I looked into GNS3 for later studies. Time to google search and come up with something that will work for me.
Thank you again. -
Optionsnetworker050184
Mod Posts: 11,962 Mod
figures I have real equipment. I looked into GNS3 for later studies. Time to google search and come up with something that will work for me.
Thank you again.
I don't use GNS3 just dynamips and dynagen. No need fro all that GUI fluff IMO. You can use a SPAN port on a switch for the same thing. You won't be able to sniff serial traffic that way though as its ethernet only. There is the "router IP traffic export capture" feature also you can look into.An expert is a man who has made all the mistakes which can be made.
