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Title: R&S Quick Notes – Switching

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With the insane amount of theory to go through before the big day comes, it is only normal for a couple of items to get lost in the masses. On top of that, regardless of the material you used to study, you are bound to come across a couple small things that you have not seen before. Apart from my 400 pages of summarized notes, I made short notes on the fly while labbing of anything I have not seen before or any beeg gothas to look out for.

Hope these help some of you!
Switching Notes

	If different VTP domain names between 2 switches, you cant use DTP. Must use manual trunking. 
	When configuring 802.1x, DO NOT forget to add “aaa authentication login default none”, else you might lock the router and forfeit any points related to that switch.
	Always confirm your MD5 to be same when configuring VTP PASSWORDS, with “sh vtp status”
	To enable WCCP on a 3550, you have to change the SDM template to ‘extended-match'
	STP Timers question-1: Change the STP timers when a port initially comes up to 44 sec.  Answer: Blocking is always 20 sec, (44-20 = 24/2) each listening and learning timers should be configured at 12 sec.
	STP Timers question-2: Change the STP timers, that in the event of convergence, delay should be no more than 20 sec. Answer: (20/2) each listening and learning timers should be configured at 10 sec.
	MAC-ACL's will only match NON-IP traffic. 3560 sees IPv6 traffic as IP-traffic, but 3550 sees IPv6 traffic as NON-IP-traffic, so a 3550 can use a MAC-ACL for IPv6 traffic.
	Ethertypes used with MAC-ACL's not on DOC-CD/CMD-Help :

- 0×0806 : IP ARP
- 0×0800 : IPv4
- 0×86DD : IPv6
- 0×4242 : CST (Common Spanning Tree)
- 0xAAAA : All Cisco proprietary (VTP, STP, CDP, DTP, UDLD, PAgP)
- 0xFFFF : all NON-IP

	VLAN-ACL's: ONLY a ACL-Permit performs the “forward”/”drop” function in the access-map. A ACL-deny will be ignored. So to deny traffic with VLAN ACL's, permit the traffic and use a “drop” action in the access-map.
	Storm-Control: Multicast amount must be equal or greater that the broadcast amount.
	Uplinkfast used when a direct link failure is detected.
	Backbonefast – used to determine indirect link failure.
	Root Bridge Election: 1-Lowest Bridge-ID (Priority [32768 ] + Sys-Id-Ext[=vlan]) & 2-Lowest MAC
	Root Port Election: 1-Lowest cost to Root, 2-Lowest upstream Bridge-ID, 3-Lowest Port-ID (Port Priority + Port Number)
	Influencing local Root Port election – change the Port Cost.
	Influencing the Root Port of directly connected downstream switch – change the Port Priority.

By CCIE 24163

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Post date: 2009-06-05 16:43:32

Post date GMT: 2009-06-05 08:43:32

Post modified date: 2010-07-24 14:32:47

Post modified date GMT: 2010-07-24 06:32:47



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