From: Gary Duncanson (gary.duncanson@googlemail.com)
Date: Thu Dec 06 2007 - 19:09:41 ART
I suppose so.
That's a very good link by Joe.
I must read it sometime :)
Gary
----- Original Message -----
From: "Scott Vermillion" <scott_ccie_list@it-ag.com>
To: "'Gary Duncanson'" <gary.duncanson@googlemail.com>
Cc: <ccielab@groupstudy.com>
Sent: Thursday, December 06, 2007 10:06 PM
Subject: RE: [SPAM]Re: I know this CCIE who wouldn't know a packet if it hit
him in the ass! ~CCIE Interview Qs~
> Good question Gary. My suspicion is that yes, the default route is at the
> very bottom of the FIB. I did a quick read of Odom's Cert Guide (3rd
> Edition) and he didn't really touch on default routes from a CEF
> perspective. However, I was reminded that the FIB is organized into a
> construct called an "mtrie." If I understand things correctly, this is
> organized such that you get a more specific match towards the top and a
> less
> specific match towards the bottom (this reduces average lookup time). So
> presumably 0.0.0.0, if present in the RIB, would be found at the very
> bottom
> of the FIB. I would guess that there would be a L2 header cached for the
> 0.0.0.0 next hop in the adjacency table.
>
> Notice my use of the words "suspicion," "presumably," and "guess" here...
>
>
> -----Original Message-----
> From: Gary Duncanson [mailto:gary.duncanson@googlemail.com]
> Sent: Thursday, December 06, 2007 2:52 PM
> To: Scott Vermillion
> Cc: ccielab@groupstudy.com
> Subject: Re: [SPAM]Re: I know this CCIE who wouldn't know a packet if it
> hit
> him in the ass! ~CCIE Interview Qs~
>
> What happens when a L3 switch receives a frame destined for a L3
> destination
>
> that is unknown to the router which has to recourse to a default route? Do
> default route interfaces and outbound L2 headers get translated into FIB?
>
> I think Odom covers some of this.
>
> Gary
> ----- Original Message -----
> From: "Scott Vermillion" <scott_ccie_list@it-ag.com>
> To: "'Jian Gu'" <guxiaojian@gmail.com>; "'Gary Duncanson'"
> <gary.duncanson@googlemail.com>
> Cc: "'Darren Johnson'" <dazza_johnson@yahoo.co.uk>;
> <ccielab@groupstudy.com>
> Sent: Thursday, December 06, 2007 9:41 PM
> Subject: RE: [SPAM]Re: I know this CCIE who wouldn't know a packet if it
> hit
>
> him in the ass! ~CCIE Interview Qs~
>
>
>> Hey all,
>>
>> Certainly it's great to know what the process would be sans CEF/MLS, but
>> in
>> modern switching architectures, we aren't actually doing these lookups
>> based
>> on flows or packet/frame arrival, right? My studies of CEF for the
>> written
>> caused me to look a little more deeply into this than I ever had
>> previously.
>> What I recall (and what Joe's article seems to confirm) is that
>> information
>> populated into the RIB gets translated into a FIB by CEF. Then the
>> adjacency table actually caches the full L2 header for each and every
>> entry
>> in the FIB.
>>
>> So before the first flow ever takes place, we've already pre-calculated
>> not
>> only the outgoing interface for every L3 destination, we've also cached
>> the
>> outbound L2 header. This all gets pushed down to ASICs that essentially
>> match on bit patterns. In other words, both L2 and L3 are switched down
>> in
>> hardware and all of this is set up at system boot time. Then the RP
>> simply
>> pushes changes in the RIB over to CEF, which maintains the FIB.
>>
>> Now where I get a bit fuzzy is how QoS policy and that sort of thing gets
>> inserted into the mix. I'm not a chip designer and I don't aspire to be.
>> I'm willing to take some things on faith, and this is probably one such
>> thing.
>>
>> And I understand you too Darren! A host or another router viewing the
>> local
>> box in question as the next hop would perform L2 encapsulation with the
>> destination MAC set to that of this local box. But I still think that,
>> due
>> to CEF, in such a case we're still just dealing with a L3 switching
>> operation vs. a L2 switching operation.
>>
>> Right?
>>
>> Scott
>>
>>
>> -----Original Message-----
>> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>> Jian
>> Gu
>> Sent: Thursday, December 06, 2007 2:12 PM
>> To: Gary Duncanson
>> Cc: Darren Johnson; ccielab@groupstudy.com
>> Subject: Re: [SPAM]Re: I know this CCIE who wouldn't know a packet if it
>> hit
>> him in the ass! ~CCIE Interview Qs~
>>
>> Assuming MACs are leaned and ARPs are all resolved.
>>
>> When a frame comes in, router/switch will do both L2 and L3 lookup at the
>> same time, and combine the result to make the final decision. If
>> destination
>> MAC is router, then L2 lookup will not yield something meaningful, L3
>> lookup will come out with MAC re-write information for nexthop for
>> destination IP, frame will then be routed. If destination MAC is not
>> router,
>> this MAC must be in the vlan's dynamic MAC table, in this case, L2 lookup
>> will yield outgoing port, L3 lookup better come with the same result,
>> this
>> frame will be L2 switched.
>>
>> Jian
>>
>> On Dec 6, 2007 12:40 PM, Gary Duncanson <gary.duncanson@googlemail.com>
>> wrote:
>>
>>> Daz,
>>>
>>> Yeah. Well it's getting later here in GB.
>>>
>>> Packet comes in..
>>>
>>> If the destination MAC address is that of the L3 switch, then it knows
>>> about
>>> it, doesn't it just switch it out the right interface?
>>>
>>> If unknown..what about ARP or routing?
>>>
>>> Im sure you know what you mean :-)
>>>
>>> Gaz
>>> ----- Original Message -----
>>> From: "Darren Johnson" <dazza_johnson@yahoo.co.uk>
>>> To: "'Gary Duncanson'" <gary.duncanson@googlemail.com>
>>> Cc: <ccielab@groupstudy.com>
>>> Sent: Thursday, December 06, 2007 8:33 PM
>>> Subject: RE: [SPAM]Re: I know this CCIE who wouldn't know a packet if it
>>> hit
>>> him in the ass! ~CCIE Interview Qs~
>>>
>>>
>>> > Hey Gaz, starting to like our late night chats ;-)
>>> >
>>> > My point was that if the destination MAC address is that of the L3
>>> switch,
>>> > it is to be routed. If it isn't and the receiving interface is L2 then
>>> it
>>> > is
>>> > switched/bridged.
>>> >
>>> > Hmmm, not sure if Im making myself clear. I know what I mean...... :-)
>>> >
>>> > Daz
>>> >
>>> > -----Original Message-----
>>> > From: Gary Duncanson [mailto:gary.duncanson@googlemail.com]
>>> > Sent: 06 December 2007 19:50
>>> > To: Darren Johnson
>>> > Cc: ccielab@groupstudy.com
>>> > Subject: [SPAM]Re: I know this CCIE who wouldn't know a packet if it
>>> > hit
>>> > him
>>> > in the ass! ~CCIE Interview Qs~
>>> >
>>> > Would that not be destination MAC known by the L3 switch (switched) as
>>> > opposed to unknown (routed)?
>>> >
>>> > Is it not switched instead of bridged ;) What about those damn ASICs?
>>> > I
>>> > have chatted offline with a guru who suspects CEF is the route of the
>>> evil
>>> > these days (no pun intended) as opposed to the MLS-SE, MLS-RP, MLSP
>>> stuff
>>> > and he may comment soon.
>>> >
>>> > You know who you are ;)
>>> > ----- Original Message -----
>>> > From: "Darren Johnson" <dazza_johnson@yahoo.co.uk>
>>> > To: "'Gary Duncanson'" <gary.duncanson@googlemail.com>; "'Jian Gu'"
>>> > <guxiaojian@gmail.com>
>>> > Cc: <ccielab@groupstudy.com>
>>> > Sent: Thursday, December 06, 2007 7:28 PM
>>> > Subject: RE: I know this CCIE who wouldn't know a packet if it hit him
>>> in
>>> > the ass! ~CCIE Interview Qs~
>>> >
>>> >
>>> >> IMHO, if the destination MAC is owned by the L3 switch, then it needs
>>> to
>>> >> be
>>> >> routed. If the destination MAC is not owned by the L3 switch, it can
>>> >> either
>>> >> bridge it (if the device is located on another interface) or drop it
>>> (if
>>> >> the
>>> >> device is located on the same interface the frame was received on).
>>> >>
>>> >> Dazzler
>>> >>
>>> >> -----Original Message-----
>>> >> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
>>> >> Of
>>> >> Gary
>>> >> Duncanson
>>> >> Sent: 06 December 2007 17:51
>>> >> To: Jian Gu
>>> >> Cc: ccielab@groupstudy.com
>>> >> Subject: Re: I know this CCIE who wouldn't know a packet if it hit
>>> >> him
>>> in
>>> >> the ass! ~CCIE Interview Qs~
>>> >>
>>> >> Sounds like the route once switch many thing to me from MLS studies..
>>> >>
>>> >> Gary
>>> >> ----- Original Message -----
>>> >> From: "Jian Gu" <guxiaojian@gmail.com>
>>> >> To: "Sohail Nedaria" <sohail.nedaria@gmail.com>
>>> >> Cc: "ccie ccie" <cciefun@gmail.com>; "Narbik Kocharians"
>>> >> <narbikk@gmail.com>; "Cisco certification" <ccielab@groupstudy.com>
>>> >> Sent: Thursday, December 06, 2007 6:54 AM
>>> >> Subject: Re: I know this CCIE who wouldn't know a packet if it hit
>>> >> him
>>> in
>>> >> the ass! ~CCIE Interview Qs~
>>> >>
>>> >>
>>> >>> Sure, here is one I like,
>>> >>>
>>> >>> How does a L3 switch router know when to L2 switch an incoming frame
>>> and
>>> >>> when to L3 switch an incoming frame?
>>> >>>
>>> >>> On Dec 5, 2007 10:00 PM, Sohail Nedaria <sohail.nedaria@gmail.com>
>>> >>> wrote:
>>> >>>
>>> >>>> Hi Guys
>>> >>>>
>>> >>>> Can you guys provide me CCIE Interview questions so i
>>> can
>>> >>>> also prepare my self well before i take on any interview.
>>> >>>>
>>> >>>> Thanks
>>> >>>> Suhail
>>> >>>> CCIE#19337
>>> >>>>
>>> >>>>
>>> >>>> On 12/6/07, ccie ccie <cciefun@gmail.com> wrote:
>>> >>>> >
>>> >>>> > Hi,
>>> >>>> >
>>> >>>> > I am going off bit, but like to share something with you.
>>> >>>> >
>>> >>>> > I gave lots of interview include CISCO, Google, Yahoo......no end
>>> >>>> > &
>>> i
>>> >>>> gave
>>> >>>> > with out any interest to join but to test myself :). I gave
>>> >>>> > interview
>>> >>>> for
>>> >>>> > small to big organization & i found you can't impress the
>>> interviewer
>>> >>>> only
>>> >>>> > by your techniqual knowledge.
>>> >>>> >
>>> >>>> > Thing to impress them as per my understanding are as.
>>> >>>> >
>>> >>>> > 1. Good Techniqual Approach
>>> >>>> > 2. If you dont know say you dont know this time, but you will
>>> >>>> > learn
>>> &
>>> >>>> find
>>> >>>> > the answer.
>>> >>>> > 3. Good troubleshooting approach (In network always answer withh
>>> >>>> refrance
>>> >>>> > to
>>> >>>> > OSI layer)
>>> >>>> > 4. Listen interviewer carefully take own time to think & answer
>>> >>>> > 5. Never underestimate interviewer who knows what the other side
>>> >>>> > person
>>> >>>> > is.
>>> >>>> > 6. Respect interviwer & appreciate him for some good question.
>>> >>>> > 7. Before go to the interview do your study about the
>>> >>>> > oganization.
>>> >>>> > 8. Last be not least. Give an impression that you respect the
>>> >>>> organization
>>> >>>> > lot, you will love to work for them, you will give longer
>>> association
>>> >>>> > &
>>> >>>> > your
>>> >>>> > placement in organization will contributing lot to generate
>>> revenue.
>>> >>>> >
>>> >>>> > Dont forget final interview is always by the management people.
>>> >>>> >
>>> >>>> >
>>> >>>> > Regards,
>>> >>>> > Mike
>>> >>>> >
>>> >>>> >
>>> >>>> >
>>> >>>> > On 12/6/07, Narbik Kocharians <narbikk@gmail.com> wrote:
>>> >>>> > >
>>> >>>> > > Darth, Are you a CCIE? I don't see your number. But what would
>>> you
>>> >>>> hate
>>> >>>> > to
>>> >>>> > > be asked in the interview? that's the question i would ask.
>>> >>>> > > I would ask him/her what are your weak points and what are your
>>> >>>> > > strong
>>> >>>> > > points. Go from there.
>>> >>>> > > Talk to him/her about some of the problems that your firm had
>>> >>>> > > and
>>> >>>> > > see
>>> >>>> > > what the person responds, but don't expect the poor CCIE to
>>> >>>> > > solve
>>> >>>> > > it
>>> >>>> for
>>> >>>> > > you
>>> >>>> > > in a second. But he/she should have an idea as to where to
>>> >>>> > > look,
>>> >>>> > > from
>>> >>>> > that
>>> >>>> > > you should know the depth of his/her knowledge.
>>> >>>> > > If you or the interviewer is experienced enough, the second
>>> >>>> > > this
>>> >>>> person
>>> >>>> > > opens his/her mouth, you should know the depth of his
>>> >>>> > > knowledge.
>>> >>>> > >
>>> >>>> > > But once again, CCIEs are not gods, they can have a bad day as
>>> >>>> > > well.
>>> >>>> > > I
>>> >>>> > > personally like to focus on the person's attitude and
>>> personality,
>>> >>>> > > obviously
>>> >>>> > > he/she got the CCIE cert, which means that the person either
>>> knows
>>> >>>> > > or
>>> >>>> > knew
>>> >>>> > > the stuff and can easily pick up the info.
>>> >>>> > >
>>> >>>> > >
>>> >>>> > > My 2 Cent.
>>> >>>> > >
>>> >>>> > > On 12/5/07, darth router <darklordrouter@gmail.com> wrote:
>>> >>>> > > >
>>> >>>> > > > Ok guys,
>>> >>>> > > >
>>> >>>> > > > there was a thread a while back talking about dumbass CCIE's.
>>> As
>>> >>>> > > > I
>>> >>>> > > prefer
>>> >>>> > > > not to be the dumbest CCIE on the planet, help me out with
>>> >>>> > > > questions
>>> >>>> > > that
>>> >>>> > > > you might ask a CCIE candidate in an interview. I have had
>>> >>>> > > > some
>>> >>>> brutal
>>> >>>> > > > interviews since I became IE. Honestly the questions seem a
>>> >>>> > > > bit
>>> >>>> basic
>>> >>>> > so
>>> >>>> > > > far, but I have had some really in depth questions about
>>> >>>> > spanning-tree,
>>> >>>> > > > troubleshootin real world EIGRP scenarios, etc.. that really
>>> >>>> > > > caught
>>> >>>> me
>>> >>>> > > off
>>> >>>> > > > guard. It's not that I could not have solved these issues,
>>> >>>> > > > had
>>> I
>>> >>>> been
>>> >>>> > > > there
>>> >>>> > > > logged into the routers, its explaining things we take for
>>> >>>> > > > granted
>>> >>>> can
>>> >>>> > > be
>>> >>>> > > > tough, especially in interviews. It seems like a lot of
>>> >>>> > > > people are amazed that a CCIE couldn't answer this or that
>>> >>>> > > > question.
>>> >>>> > > > Personally, I am trying to come up with a knowledge
>>> >>>> > > > maintanance
>>> >>>> plan,
>>> >>>> > > > like reading a chapter in the exam cert guide every week. The
>>> >>>> > > > tasks
>>> >>>> I
>>> >>>> > > > do not do on a daily basis fade quickly.
>>> >>>> > > >
>>> >>>> > > >
>>> >>>> > > > I have of late been going way back to basics, reading up on
>>> >>>> > > > TCP/IP
>>> >>>> > > flows,
>>> >>>> > > > Ethernet, ARP, looking at packet sniffing traces, etc..
>>> >>>> > > > Someone
>>> >>>> > > > made
>>> >>>> > > > mention
>>> >>>> > > > of the CAM table populating entries, so I read up on that
>>> >>>> > > > too.
>>> >>>> > > >
>>> >>>> > > > I certainly don't know everything, but I would love to. Care
>>> >>>> > > > to
>>> >>>> > > > give
>>> >>>> > me
>>> >>>> > > > some
>>> >>>> > > > example questions you might ask a CCIE in an interview, or
>>> >>>> > technologies
>>> >>>> > > > you
>>> >>>> > > > would expect to have him/her to have down pat?
>>> >>>> > > >
>>> >>>> > > > DR
>>> >>>> > > >
>>> >>>> > > >
>>> >>>> >
>>> > _______________________________________________________________________
>>> >>>> > > > Subscription information may be found at:
>>> >>>> > > > http://www.groupstudy.com/list/CCIELab.html
>>> >>>> > > >
>>> >>>> > >
>>> >>>> > >
>>> >>>> > >
>>> >>>> > > --
>>> >>>> > > Narbik Kocharians
>>> >>>> > > CCIE# 12410 (R&S, SP, Security)
>>> >>>> > > CCSI# 30832
>>> >>>> > > www.MicronicsTraining.com
>>> >>>> > > Sr. Technical Instructor
>>> >>>> > > www.Net-WorkBooks.com
>>> >>>> > >
>>> >>>> > >
>>> >>>>
>>> _______________________________________________________________________
>>> >>>> > > 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
>>> >>>> >
>>> >>>>
>>> >>>>
>>> >>>>
>>> >>>> --
>>> >>>> Thanks And Regards
>>> >>>> Suhail.U.Nedaria
>>> >>>> 9833256425
>>> >>>> CCIE# 19337.
>>> >>>>
>>> >>>>
>>> _______________________________________________________________________
>>> >>>> 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
>>> >>
>>> >>
> _______________________________________________________________________
>>> >> Subscription information may be found at:
>>> >> http://www.groupstudy.com/list/CCIELab.html
>>> >>
>>> >>
>>> >>
>>> >> ___________________________________________________________
>>> >> Does your mail provider give you FREE antivirus protection?
>>> >> Get Yahoo! Mail http://uk.mail.yahoo.com
>>> >>
>>> >
>>> >
>>> >
>>> > ___________________________________________________________
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>>
>> _______________________________________________________________________
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