Monday, July 29, 2013

CCIE DC: Unfiltered stuff learnt on first day of bootcamp

Hi Guys

This blog post may be incoherent, that's right, even more incoherent than my normal posts ha ha as it's just a collection of notes I have made on my first day of bootcamp

Port Groupings:
Oddly enough, on the M line cards, ports are grouped in an ASIC from ports 1,3,5,7, then another port group 2,4,6,8, so side to side, F line cards it's ports 1 and 2 in one port group, 3 and 4 in the next etc.

show running-config vdc-all from the default vdc will show you all VDC's running config all at once, kind of like copy run start vdc-all

on a SPAN destination port, the command:

switchport monitor

is NOT mandatory, but it turns off things like spanning-tree etc so could really be a good idea.

a few useful commands:

show spanning-tree blockedports
show vtp interface
Simulate PVST, a command that confused me greatly, is very simple: it allows MSTP to simulate a PVST protocol to ports where the other end is not configured for MSTP, it is not a complicated command is on by default. no reason to get super confused by it.

spanning-tree pathcost method [short | long} can be used to change the cost of spanning-tree interfaces, although by default they will show in the config with long values, they are not advertsied with long values unless you change the above, which will change the length of the bits from 16 to 32 for the cost

lacp rate don't forget to configure on both ends

in EIGRP you can specify a process name THEN an as:

router eigrp CCIERANTS
autonomous-system number 666

key-chain: you can just not specify a valid or accepted lifetime and the key will be valid forever

Only two possible types of interfaces (network interfaces) with OSPF on n7k: point to point and broadcast, because the N7k only does ethernet.

Loopback int's will always advertise as /32's in ospf unless you explicitally say:

int lo0
ip ospf advertise-subnet

when you redistribute in nexus, you must have a route-map, which begs the question: what if i just want to redistribute all routes?

make a route-map with permit and no conditions:

route-map redistall permit 10

To redistribute connected is now 'redistribute direct'

ip bfd optimize subinterfaces command means that BFD will only send one hello on a physical int even if multiple subinterfaces exist.

the echo-mode for BFD is used when you have a neighbor whom you don't use a similar routing protocol with but you want to send BFD's to them.

BFD will miss three packets by default

IP PIM has a ssm-range command.

if a FEX link dies and your not using a port channel, you can manually redistribute fex with:

fex pinning redistribute



  1. Thanks for sharing this info. Even when not organized, it's useful.

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