Re: Router-ID & BGP address-family questions

OK, thanks for the clarification Brian. It would make sense that
Cisco would have corrected this, if ever it was a limitation. Why
would EIGRPv6 not pull from an interface configured with an IPv4
address like all of the other protocols? Never made sense to me but
it's definitely in my notes. Also, the 4th edition of the Cert Guide
has the following to say (page 918):

"IPv6 EIGRP requires a routing process to be defined and enabled (no
shutdown) and a router ID (in 32-bit IPv4 address format) to be
manually assigned using the router-id command, both of which must be
done in IPv6 router configuration mode before the IPv6 EIGRP routing
process can start. These are two of the differences between EIGRP for
IPv4 and IPv6."

Then on the next page it goes on to say the following:

"Router ID - EIGRP for IPv6 requires a 32-bit router ID (a dotted-
decimal IPv4 address) to be configured before it starts. A router
does not complain about the lack of an EIGRP RID, however, so remember
to configure one statically when doing a no shutdown in the routing
process."

Perhaps I read too much into statements such as these. Nowhere does
the above text explicitly state that an IPv4 address absolutely will
not be inherited if configured on an interface. However, it could
easily be interpreted to suggest as much. And come to think of it,
I'm not sure EIGRPv6 (which is apparently now referred to as "IPv6
EIGRP!") was even within the scope of the lab when I was preparing for
it, so it may be the case that I've never labbed it to see for myself
one way or the other...

____________________________________________
There are only 10 types of people in the world:
Those who understand binary and those who do not...

On Feb 1, 2011, at 12:48 , Brian McGahan wrote:

> No, it's not needed in new versions. It's possible it was needed
> when the feature was first released. The IPv6 protocols should
> normally pull their RIDs from an IPv4 interface just like their v4
> counterparts. Like you said though, if you're not running dual-stack
> then you need to configure it manually.
>
> Brian McGahan, CCIE #8593 (R&S/SP/Security)
> bmcgahan_at_INE.com
>
> Internetwork Expert, Inc.
> http://www.INE.com
>
> On Feb 1, 2011, at 1:44 PM, "Scott M Vermillion" <scott_ccie_list_at_it-ag.com
> > wrote:
>
>> Well, I certainly haven't encountered EIGRPv6 in the real world and
>> the code I'm running in my current lab setup doesn't support it, so
>> perhaps I am mistaken. My old notes from R&S lab prep state that
>> the 'router-id' command is required under the EIGRPv6 process,
>> regardless of whether or not any interfaces have been assigned IPv4
>> addresses. It wouldn't be the first time one of my notes was
>> either just flat out incorrect or had become OBE over the past few
>> years...
>>
>> ____________________________________________
>> There are only 10 types of people in the world:
>> Those who understand binary and those who do not...
>>
>> On Feb 1, 2011, at 12:25 , Brian McGahan wrote:
>>
>>> In IPv6 as well. All designs can be solved without the need for
>>> the use of the router-I'd command, both in IPv4 and IPv6. The only
>>> issue is that within the scope of the lab, they may say don't do X
>>> or dint use command Y, in which case you may be limited as to your
>>> viable solutions.
>>>
>>> Brian McGahan, CCIE #8593 (R&S/SP/Security)
>>> bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com>
>>>
>>> Internetwork Expert, Inc.
>>> http://www.INE.com
>>>
>>>
>>> On Feb 1, 2011, at 12:58 PM, "Scott M Vermillion" <scott_ccie_list_at_it-ag.com
>>> <mailto:scott_ccie_list_at_it-ag.com>> wrote:
>>>
>>>> Likewise there is never a case where you *have* to define the
>>>> router-I'd manually.
>>>
>>> In the case of IPv4, anyway, no?
>>>
>>> ____________________________________________
>>> There are only 10 types of people in the world:
>>> Those who understand binary and those who do not...
>>>
>>> On Feb 1, 2011, at 10:47 , Brian McGahan wrote:
>>>
>>> Likewise there is never a case where you *have* to define the
>>> router-I'd manually. Whether a routing process is in the global
>>> table or a vrf table, the highest loopback that is up/up when the
>>> process starts will be the RID. If no loopback exists then the
>>> highest address on any other link will be used.
>>>
>>> Setting the RID is good design practice, and can make
>>> troubleshooting easier. If different routers have the same RID,
>>> like in an anycast design, different protocols can have different
>>> problems.
>>>
>>> So now the question should be, what are these problems? If you
>>> know this then it will tell you when it's a good idea to set the
>>> RID manually.
>>>
>>> Brian McGahan, CCIE #8593 (R&S/SP/Security)
>>> <mailto:bmcgahan_at_INE.com>bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com>
>>>
>>> Internetwork Expert, Inc.
>>> http://www.INE.com
>>>
>>> On Feb 1, 2011, at 10:40 AM, "Hussam EL Kebbi" <hussamkibbi_at_hotmail.com
>>> > wrote:
>>>
>>> ccielab_at_groupstudy.com
>>>
>>>
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Received on Tue Feb 01 2011 - 13:07:27 ART