From: Hobbs (deadheadblues@gmail.com)
Date: Sun Feb 01 2009 - 00:18:19 ARST
Well since I got rack session going on:
R6(config)#router bgp 256
R6(config-router)#bgp router-id 0.0.0.1
%Invalid router-id 0.0.0.1
R6(config-router)#bgp router-id 255.255.255.255
%Invalid router-id 255.255.255.255
R6(config-router)#bgp router-id 224.0.0.1
%Invalid router-id 224.0.0.1
R6(config-router)#bgp router-id 223.255.255.255
R6(config-router)#
R6#sho ver | inc bin
System image file is "flash:c2800nm-adventerprisek9-mz.124-3a.bin"
}\/\/{
| |
(.)(.)
| C |)
(___/|
)__|
/ \\
/ \\
:D
On Sat, Jan 31, 2009 at 6:56 PM, swm@emanon.com <swm@emanon.com> wrote:
> The router-id in both is simply a 32-bit number.
>
> Your call.
>
> Scott
>
>
> ---- Message from "ciscozest" <ciscozest@gmail.com> at 2009-02-01 08:11:46
> ------
>>
>>
>>So in case of OSPF and BGP exist on the same router, does the router ID must
> be pingable or just a valid IPv4 address?
>>Thanks.
>>
>>
>>
>>From: Narbik Kocharians [mailto:narbikk@gmail.com]
>>Sent: Sunday, 1 February 2009 4:26 AM
>>To: ciscozest
>>Cc: swm@emanon.com; Jared Scrivener; Jason Madsen; Cisco certification; Cisco
> certification
>>Subject: Re: about OSPF router ID
>>
>>
>>I totally agree with Scott, the OSPF router id is a 32 bit dotted decimal
> number, it can be an IPv4 address, but it can also be any dotted decimal
> number like "0.0.0.1" for R1 and so forth.
>>
>>
>>
>>One problem that you may run in to (In a CCIE LAB) is when you have OSPF and
> BGP with synchronization enabled in an AS, the router that redistributes the
> BGP routes into OSPF must have the same router-id configured on both routing
> protocols (meaning OSPF and BGP router-id must be identical on that router)
> and in this case you won't be able to use anything other than a valid IP
> address, because BGP's router-id must be a valid IP address.
>>
>>
>>
>>Hope this helped.
>>
>>On Sat, Jan 31, 2009 at 3:57 AM, ciscozest <mailto:ciscozest@gmail.com >
> wrote:
>>Dear Scott, Jared, Roy and Jason,
>>
>>Thank you all for the input. Really appreciate that. Have a nice weekend :)
>>
>>
>>-----Original Message-----
>>From: mailto:swm@emanon.com [mailto:mailto:swm@emanon.com ]
>>Sent: Saturday, 31 January 2009 3:23 PM
>>To: Jared Scrivener; 'Jason Madsen'; 'ciscozest'
>>Cc: 'Cisco certification'; 'Cisco certification'
>>
>>
>>Subject: RE: about OSPF router ID
>>
>>Actually, it not only doesn't need to be pingable, but it doesn't even need
> to be a valid IPv4 address. It's simply a 32-bit number.
>>
>>If you're bored, make your router-id's 240.1.1.1, 240.1.1.2, 240.1.1.3, etc.
> Definitely can't put that on an IP interface... Definitely can't ping it.
> But it works just fine.
>>
>>Jared's got a point about name lookups, but on the other hand, if you
> properly populate your DNS lookups you'll be good on that one!
>>
>>Real life, most people use a loopback, whatever your main management
> interface happens to be. Just keeps things simple. But it's just a 32-bit
> number, so the fact that it relates to an actual IP address is for OUR
> benefit, not the routers'!
>>
>>Scott
>>
>>
>>---- Message from "Jared Scrivener" <mailto:jscrivener@ipexpert.com > at
> 2009-01-30 21:25:18 ------
>>>Whilst it is true that an OSPF Router ID doesn't have to be pingable, it
>>>generally makes life easier to use a reachable IP (normally Loopback 0).
>>>
>>>Let's say that you are asked to also turn on "ip ospf domain-lookup" which
>>>will translate your neighbor's Router-ID into a DNS name (which will either
>>>be defined by a hosts file or received via DNS).
>>>
>>>If you do it via hosts entries and your are ALSO a DNS server then your DNS
>>>clients would receive an unreachable IP address when they ping via DNS
> name.
>>>
>>>I know that's a rare case, but given the nature of question interdependency
>>>on the lab (and the evil nature of workbook vendors) I personally use L0 as
>>>my OSPF Router-ID (and set it manually using the "router-id" command) every
>>>time unless otherwise directed.
>>>
>>>Cheers,
>>>
>>>Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP
>>>Technical Instructor - IPexpert, Inc.
>>>Telephone: +1.810.326.1444
>>>Fax: +1.810.454.0130
>>>Mailto: mailto:jscrivener@ipexpert.com
>>>
>>>-----Original Message-----
>>>From: mailto:nobody@groupstudy.com [mailto:mailto:nobody@groupstudy.com ]
> On Behalf Of
>>>Jason Madsen
>>>Sent: Friday, 30 January 2009 9:01 PM
>>>To: ciscozest
>>>Cc: Cisco certification; Cisco certification
>>>Subject: Re: about OSPF router ID
>>>
>>>OSPF Router IDs can be any UNIQUE IPv4 address...they don't have to be
>>>addresses assigned to an interface.
>>>
>>>On Fri, Jan 30, 2009 at 6:56 PM, ciscozest <mailto:ciscozest@gmail.com >
> wrote:
>>>
>>>> Hi all,
>>>>
>>>>
>>>>
>>>> I read Cisco press book stated that OSPF router ID do not need to be
>>>> pingable. In this case if I use a router ID which is not assigned to any
>>>> interface on that router, would this cause any issue such as OSPF
>>>> adjacency,
>>>> LSA table advertisement, etc? Has anyone do this before and can enlighten
>>>> me? Thanks.
>>>>
>>>>
>>>> Blogs and organic groups at http://www.ccie.net/"
>>target="_blank
>>>>
>>>> _______________________________________________________________________
>>>> Subscription information may be found at:
>>>> http://www.groupstudy.com/list/CCIELab.html
>>>
>>>
>>>Blogs and organic groups at http://www.ccie.net/
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>>>
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> 14:34
>>
>>
>>
>>
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>>
>>
>>
>>
>>
>>
>>--
>>Narbik Kocharians
>>CCSI#30832, CCIE# 12410 (R&S, SP, Security)
>>http://www.MicronicsTraining.com www.MicronicsTraining.com
>>http://www.Net-Workbooks.com www.Net-Workbooks.com
>>Sr. Technical Instructor
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> 17:31:00
>
>
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>
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