Hello All I joined this list a month ago and have enjoyed reading the messages I have received to date
I am looking for some LAB space which I could use and curious if anyone could make some suggestions I am in the US in the Philadelphia Area I have passed my written in July Any help would be appreciated Thanks Tom Jennings On Sep 23, 2011, at 12:00 PM, [email protected] wrote: > Send CCIE_Wireless mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > http://onlinestudylist.com/cgi-bin/mailman/listinfo/ccie_wireless > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of CCIE_Wireless digest..." > > > Today's Topics: > > 1. Re: CCIE_Wireless Digest, Vol 30, Issue 16 (Jason Boyers) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 23 Sep 2011 11:20:16 -0400 > From: "Jason Boyers" <[email protected]> > To: "'Aaron Leonard'" <[email protected]> > Cc: [email protected], > [email protected] > Subject: Re: [OSL | CCIE_Wireless] CCIE_Wireless Digest, Vol 30, Issue > 16 > Message-ID: <[email protected]> > Content-Type: text/plain; charset="us-ascii" > > Just to come back on this, after some testing and discussion with Aaron, > here's where we are with CDP: > > 1) Access ports (no matter the device) - sent untagged and therefore > received on whatever VLAN the access port is associated with > 2) Trunk ports (except for WLCs and 4.2 APs) - sent on VLAN 1, whether or > not this is the native VLAN and whether or not it is in a spanning-tree > forwarding state > 3) WLC and 4.2 based APs - sent untagged, and thus are associated with the > native VLAN, whatever that may be > > Cisco has done work on the APs since 4.2 which resulted in the change for > lightweight APs (apparently it was causing issues for PoE, particularly with > the 1250s.) The WLCs (as of 7.0.116.0) are the only devices in the mix that > are using the native VLAN for CDP. > > Thanks Aaron for your help and clarification on this! > > Jason Boyers - CCIE #26024 (Wireless) > Technical Instructor - IPexpert, Inc. > Mailto: [email protected] > > > -----Original Message----- > From: Aaron Leonard [mailto:[email protected]] > Sent: Wednesday, September 21, 2011 10:31 PM > To: Jason Boyers > Cc: [email protected]; > [email protected] > Subject: Re: [OSL | CCIE_Wireless] CCIE_Wireless Digest, Vol 30, Issue 16 > > Inline: > > On 9/21/2011 2:58 PM, [email protected] (Jason Boyers) wrote: >> Thank you for the clarification. In looking at various documents, >> there is a lot of confusion. From what you are stating: >> >> Access Port - sent on the VLAN for which interface is configured > > Well, if it's an access port (untagged), then there *is* no VLAN (not from > the perspective of the AP at any rate.) So the AP just sends the CDP packet > out untagged (as it sends *all* packets), in that case. > > A *switch* has a notion of what VLAN if any is configured on an access port, > but an *AP* does not. > >> Trunk Port - sent on VLAN 1, whether or not VLAN 1 is tagged and >> whether or not VLAN 1 is allowed and in a spanning-tree forwarding >> state for that port > > Well, an AP doesn't have the notion of "allowed" VLANs. The VLANs (i.e. > subinterfaces of the LAN interface) are either configured or not. > > But so anyway - the AP *always* sends CDP in VLAN1, *if* its LAN port is > configured for VLANs. > > (Here I am not sure about what if VLAN1 is in a spanning-tree blocked state > - I would assume then that we would *not* send CDP, but would not wager cash > on that point.) > >> Is that another way of putting it? That is different than my >> understanding has been (where CDP is sent untagged on an access or >> trunk port - period.) > > Yep, the notion that CDP is always sent untagged is quite incorrect. (A > notion that is widely held within Cisco as well, in fact by many developers > :) > > I would like here to post a reference to the CDP spec but unfortunately it > is confidential. As I reread it for the n'th time, I can now see that there > are two alternate possible interpretations: > > One is that, for an 802.1q encapsulated link, it should always be sent with > tagged in VLAN 1, and the other is that, for a link that has both tagged and > untagged frames, it should be sent untagged. > > Unfortunately, different implementations have adopted different > interpretations. The AP's interpretation is the VLAN 1 one. > >> I just did a packet capture on an interface connected to a WLC. That >> interface only allows specified VLANs (which don't include VLAN 1) and >> a separate native VLAN (which is 999 in this case, which doesn't even >> exist as a VLAN on the switch.) In the packet capture, CDP was tagged >> with VLAN 999 when coming from the WLC. Everything else was tagged >> with the Management VLAN (no clients currently on the WLC.) > > Well, I was speaking specifically about (WNBU) IOS, *not* about the WLC. > With the WLC, all bets are off. > > I don't quite get your scenario here. You say that your native VLAN is 999, > and that you see CDP tagged with VLAN 999 coming from the WLC. > Now, on the WLC, you configure a "native" (i.e. *untagged*) VLAN as 0 ... so > you're saying that you have some interface configured on the WLC as tagged > VLAN 999? Some interface other than the management interface? > > I'm skeptical of this ... its sounds more like maybe the WLC just transmits > CDP as untagged. > >> I appreciate your help in working through this, both for understanding >> as well as for proper documentation on Cisco's site. > > It sounds like what I *really* need to do is to drive some consensus at > Cisco on this point ... although higher priority (of course) is to study for > my imminent CCIE lab ... > > Cheers, > > Aaron > > > > ------------------------------ > > _______________________________________________ > CCIE_Wireless mailing list > [email protected] > http://onlinestudylist.com/cgi-bin/mailman/listinfo/ccie_wireless > > > End of CCIE_Wireless Digest, Vol 30, Issue 19 > ********************************************* _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? 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