Comments for CCIE Blog http://blog.ipexpert.com CCIE Candidates blog for all technical overviews relating to CCIE R&S, CCIE Voice, CCIE Security & CCIE SP Thu, 02 Feb 2012 07:42:46 +0000 hourly 1 http://wordpress.org/?v=3.1.2 Comment on Old CCIE Myths: VLAN 1 by gkoper http://blog.ipexpert.com/2011/01/19/old-ccie-myths-vlan-1/comment-page-1/#comment-89290 gkoper Thu, 02 Feb 2012 07:42:46 +0000 http://blog.ipexpert.com/?p=5874#comment-89290 Hi In my case I have connected pairs of switches HP and cisco. It seems that there is no need for native vlan on either end...I have configuration where on cisco native vlan 1 is shutdown and on HP native (default) vlan 1 is in state "no untagged" on uplink port.Even that MST BPDU are exchanged over trunk with 2 other vlans.It would be good if someone could explain me why? Then recommendation from HP or Cisco that native vlan is required are incorrect. BR Grzegorz Hi

In my case I have connected pairs of switches HP and cisco.
It seems that there is no need for native vlan on either end…I have configuration where on cisco native vlan 1 is shutdown and on HP native (default) vlan 1 is in state “no untagged” on uplink port.Even that MST BPDU are exchanged over trunk with 2 other vlans.It would be good if someone could explain me why? Then recommendation from HP or Cisco that native vlan is required are incorrect.
BR
Grzegorz

]]> Comment on Common Student Questions–Part 7: Does the Proctor Reboot my Rack? by mjolnir http://blog.ipexpert.com/2011/12/14/common-student-questions%e2%80%93part-7-does-the-proctor-reboot-my-rack/comment-page-1/#comment-88701 mjolnir Tue, 31 Jan 2012 03:26:43 +0000 http://blog.ipexpert.com/?p=9282#comment-88701 Well, I haven't sat one of these lab exams yet, but I would actually expect that if someone at CCIE level was to leave a switch or router in a state where it would not survive a reboot, that should be a fail. Surely we all know by now to save all changes to our configurations? Well, I haven’t sat one of these lab exams yet, but I would actually expect that if someone at CCIE level was to leave a switch or router in a state where it would not survive a reboot, that should be a fail. Surely we all know by now to save all changes to our configurations?

]]> Comment on Ryan Hicks, World's First CCDE Answers YOUR Questions! by Microsoft http://blog.ipexpert.com/2009/04/06/ryan-hicks-worlds-first-ccde-answers-your-questions/comment-page-1/#comment-88312 Microsoft Sun, 29 Jan 2012 19:05:07 +0000 http://ipexpert.ccieblog.com/?p=799#comment-88312 <strong>Helps...</strong> [...]Ryan Hicks, World's First CCDE Answers YOUR Questions![...]... Helps…

[...]Ryan Hicks, World's First CCDE Answers YOUR Questions![...]…

]]> Comment on BPDU Filter and BPDU Guard by Don http://blog.ipexpert.com/2010/12/06/bpdu-filter-and-bpdu-guard/comment-page-1/#comment-88180 Don Sun, 29 Jan 2012 06:58:56 +0000 http://blog.ipexpert.com/?p=5477#comment-88180 Follow up to last post I said "I have also noticed that the switch sends bpdus but does not receive any. it is like as if bpdufuilter has been enabled at the same time. NOTE: I have NOT applied the bpdugilter command." It is not receiving any BPDUs because the router is not sending any. The switch is the root bridge so it is sending BPDUs but not receiving any. If I change the router to be the root bridge then I will receive bpdus. Follow up to last post

I said

“I have also noticed that the switch sends bpdus but does not receive any. it is like as if bpdufuilter has been enabled at the same time. NOTE: I have NOT applied the bpdugilter command.”

It is not receiving any BPDUs because the router is not sending any. The switch is the root bridge so it is sending BPDUs but not receiving any. If I change the router to be the root bridge then I will receive bpdus.

]]> Comment on BPDU Filter and BPDU Guard by Don http://blog.ipexpert.com/2010/12/06/bpdu-filter-and-bpdu-guard/comment-page-1/#comment-87998 Don Sat, 28 Jan 2012 08:00:01 +0000 http://blog.ipexpert.com/?p=5477#comment-87998 this is confusing and spending far too much time on this trivia but anyhow.... i have a 3560 switch connected to a 2801 router. running pvst. my test consist of turning on bridging on the fa0/0 of the router. portfast global or portfast interface has the same effect. it disables portfast when it receives a bpdu. shutting the interfaces and bringing them back up causes the interface to forward immediately. i believe it will only revert to non portfast state if the interfacce goes to STP blocking state. I have also noticed that the switch sends bpdus but does not receive any. it is like as if bpdufuilter has been enabled at the same time. NOTE: I have NOT applied the bpdugilter command. this is confusing and spending far too much time on this trivia but anyhow….

i have a 3560 switch connected to a 2801 router. running pvst. my test consist of turning on bridging on the fa0/0 of the router.

portfast global or portfast interface has the same effect. it disables portfast when it receives a bpdu. shutting the interfaces and bringing them back up causes the interface to forward immediately. i believe it will only revert to non portfast state if the interfacce goes to STP blocking state.

I have also noticed that the switch sends bpdus but does not receive any. it is like as if bpdufuilter has been enabled at the same time. NOTE: I have NOT applied the bpdugilter command.

]]> Comment on Introduction To Catalyst 3560 QoS by Rizwan http://blog.ipexpert.com/2010/05/26/introduction-to-catalyst-3560-qos/comment-page-1/#comment-87323 Rizwan Mon, 23 Jan 2012 22:42:54 +0000 http://blog.ipexpert.com/?p=3422#comment-87323 Hi, I have small query...What if i don't want to trust any incoming packet cos or dscp values? how will the map be applied to the packets? I mean i think i have to explicitly set the dscp value in a police-map is it right? Plus in the configuration guide it is said that queuing can be based on CoS or DSCP. Isn't the map values only for internal use? i mean if you trust a value in the incoming packet why will switch map it to something else and leave it that way? The way i see it is if you explicitly set the DSCP or CoS value for a traffic then it is carried through out the network else it is just the same value that you trusted and switch will only use the map for queuing purpose (Internal use only). I am a bit confused please help me out Hi,
I have small query…What if i don’t want to trust any incoming packet cos or dscp values? how will the map be applied to the packets? I mean i think i have to explicitly set the dscp value in a police-map is it right? Plus in the configuration guide it is said that queuing can be based on CoS or DSCP. Isn’t the map values only for internal use? i mean if you trust a value in the incoming packet why will switch map it to something else and leave it that way? The way i see it is if you explicitly set the DSCP or CoS value for a traffic then it is carried through out the network else it is just the same value that you trusted and switch will only use the map for queuing purpose (Internal use only). I am a bit confused please help me out

]]> Comment on Converting IOS AP Back to Lightweight by Rohan http://blog.ipexpert.com/2011/10/27/converting-ios-ap-back-to-lightweight/comment-page-1/#comment-87188 Rohan Sun, 22 Jan 2012 11:58:15 +0000 http://blog.ipexpert.com/?p=8705#comment-87188 Hello Jason That was a wonderful article.. I am working on a project that requires conversion of several WAP placed at different sites to LAP. All the sites use same SSID. The WLC is placed at the DC.The DHCP server is in the DC and has scopes defined for entire enterprise network. The WAP are in standalone mode now. When users try to connect using wireless, the traffic flow is as follows: PC issues DHCP request-----> standalone WAP----> forwards this request to the site router which has a helper-ip--->request converted to a uicast with the routerip as src and helper-ip as destination----> sent to DHCP--> DHCP determines the cope from where the IP is to be assigned using the src of the request----> IP assigned is sent to the router ---> the IP then assigned to the machine.. Could you help me understand this flow when the WAP is converted to the LAP?. Regards Rohan Hello Jason

That was a wonderful article.. I am working on a project that requires conversion of several WAP placed at different sites to LAP. All the sites use same SSID.

The WLC is placed at the DC.The DHCP server is in the DC and has scopes defined for entire enterprise network.

The WAP are in standalone mode now. When users try to connect using wireless, the traffic flow is as follows:

PC issues DHCP request—–> standalone WAP—-> forwards this request to the site router which has a helper-ip—>request converted to a uicast with the routerip as src and helper-ip as destination—-> sent to DHCP–> DHCP determines the cope from where the IP is to be assigned using the src of the request—-> IP assigned is sent to the router —> the IP then assigned to the machine..

Could you help me understand this flow when the WAP is converted to the LAP?.

Regards

Rohan

]]> Comment on Creating a Study Plan for the CCIE Voice Lab by Juan http://blog.ipexpert.com/2011/03/02/creating-a-study-plan-for-the-ccie-voice-lab/comment-page-1/#comment-87159 Juan Sun, 22 Jan 2012 03:32:01 +0000 http://blog.ipexpert.com/?p=6261#comment-87159 4th week missing, or was a bug in the row ? 4th week missing, or was a bug in the row ?

]]> Comment on Follow-Up on OSPF and BGP Puzzle by Yap Chin Hoong http://blog.ipexpert.com/2012/01/09/follow-up-on-ospf-and-bgp-puzzle/comment-page-1/#comment-87026 Yap Chin Hoong Fri, 20 Jan 2012 15:37:34 +0000 http://blog.ipexpert.com/?p=9650#comment-87026 Marko, hopefully no one ever learnt and implemented the last configuration section into production networks. :D Marko, hopefully no one ever learnt and implemented the last configuration section into production networks. :D

]]> Comment on Follow-Up on OSPF and BGP Puzzle by Yap Chin Hoong http://blog.ipexpert.com/2012/01/09/follow-up-on-ospf-and-bgp-puzzle/comment-page-1/#comment-87024 Yap Chin Hoong Fri, 20 Jan 2012 15:29:04 +0000 http://blog.ipexpert.com/?p=9650#comment-87024 oh man this is really good stuffs!!! :-) oh man this is really good stuffs!!! :-)

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