From: Fahad Khan (fahad.khan@gmail.com)
Date: Mon Jul 07 2008 - 05:25:01 ART
here is the scenario
R1(s1/0 - 10.0.0.1/8) ---------------(s1/0-10.0.0.2/8) R2
R1(s1/1 - 10.0.0.1/8) ---------------(s1/0-10.0.0.3/8) R3
R1# sh ip route
C 10.0.0.0/8 is directly connected, Serial1/0
is directly connected, Serial1/1
-when R2 pings to R1(10.0.0.1), its fine, but
-when R3 pings to R1(10.0.0.1), it wont get reply since the "debug ip
packet" on R1 shows that R1 goes to reply R3 from its serial1/0 interface
where R2 is connected, "debug ip packet" on R2 shows that R2 is getting
reply .
is this a bug? now router is confused to send traffic....
Dear Roman,
Kindly tell me the logic in case of Frame-relay subinterfaces..?
On Sun, Jul 6, 2008 at 5:40 PM, Jason Madsen <madsen.jason@gmail.com> wrote:
> BVIs seem to work just fine too.
>
> Jason
>
>
> On Sun, Jul 6, 2008 at 2:00 PM, Edison Ortiz <edisonmortiz@gmail.com>
> wrote:
>
>> Additionally, 'ip unnumbered'?
>>
>>
>>
>> Let's consider assigning IP addresses to the interfaces of a router using
>> a
>> class B network that has been subnetted using eight bits of subnetting.
>> Every interface requires a unique subnet. Although each point-to-point
>> serial connection has only two end points to address, if we assign an
>> entire
>> subnet to each serial interface, we use 254 available addresses for each
>> interface where only two addresses are needed. If we use IP unnumbered on
>> each serial interface, we save address space; the address of a LAN
>> interface
>> is "borrowed" and used as the source address for routing updates and
>> packets
>> sourced from the serial interface. In this way, address space is
>> conserved.
>> IP unnumbered only makes sense for point-to-point links.
>>
>> A router receiving a routing update installs the source address of the
>> update as the next hop in its routing table. Normally, the next hop is a
>> directly-connected network node. This is no longer the case if we use IP
>> unnumbered because each serial interface "borrows" their IP address from a
>> different LAN interface, each in a different subnet and possibly in a
>> different major network. When IP unnumbered is configured, routes learned
>> through the IP unnumbered interface have the interface as the next hop
>> instead of the source address of the routing update. Thus we avoid an
>> invalid next hop address problem due to the source of the routing update
>> coming from a next hop that is not directly connected.
>>
>>
>> http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080
>> 094e8d.shtml#ip_ip_un<http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094e8d.shtml#ip_ip_un>
>>
>>
>>
>>
>>
>>
>>
>> Edison Ortiz
>>
>> Routing and Switching, CCIE # 17943
>>
>>
>>
>> -----Original Message-----
>> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>> Fahad Khan
>> Sent: Sunday, July 06, 2008 3:45 PM
>> To: Sadiq Yakasai
>> Cc: Joseph Saad; Cisco certification
>> Subject: Re: IP address on serial interfaces of a router
>>
>>
>>
>> What is the logic behined that I can assign 10.0.0.1/24 (exactly the same
>> ip
>>
>> address) on two serial interfaces of a single router???
>>
>>
>>
>>
>>
>> R1#sh run
>>
>>
>>
>> ---output omitted---
>>
>>
>>
>> interface Serial1/0
>>
>> ip address 10.0.0.1 255.0.0.0
>>
>> serial restart-delay 0
>>
>> !
>>
>> interface Serial1/1
>>
>> ip address 10.0.0.1 255.0.0.0
>>
>> serial restart-delay 0
>>
>>
>>
>>
>>
>> Wont the router be confused when it will forward traffic for
>>
>> 10.0.0.0/24network??
>>
>>
>>
>> Thanks and regards,
>>
>>
>>
>>
>>
>>
>>
>> On 7/6/08, Sadiq Yakasai <sadiqtanko@gmail.com> wrote:
>>
>> >
>>
>> > Huh????
>>
>> >
>>
>> > And how is this exactly related to ethernet again? :-)
>>
>> >
>>
>> > We digress again!
>>
>> >
>>
>> >
>>
>> > _______________________________________________________________________
>>
>> > Subscription information may be found at:
>>
>> > http://www.groupstudy.com/list/CCIELab.html
>>
>> >
>>
>> >
>>
>> >
>>
>> >
>>
>> >
>>
>>
>>
>>
>>
>> --
>>
>> Fahad Khan
>>
>>
>>
>>
>>
>> _______________________________________________________________________
>>
>> Subscription information may be found at:
>>
>> http://www.groupstudy.com/list/CCIELab.html
>>
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>>
>>
>>
>>
>>
>
-- FAHAD KHAN
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