From: Jian Gu (guxiaojian@gmail.com)
Date: Thu Dec 06 2007 - 19:27:22 ART
The chips do not care, 0.0.0.0/0 entry is no different from
111.111.111.0/24entry.
On Dec 6, 2007 1:52 PM, Gary Duncanson <gary.duncanson@googlemail.com>
wrote:
> 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
> >> >>
> >> >
> >> >
> >> >
> >> > ___________________________________________________________
> >> > Now you can scan emails quickly with a reading pane. Get the new
> Yahoo!
> >> > Mail. http://uk.docs.yahoo.com/nowyoucan.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
>
> _______________________________________________________________________
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