EtherChannel

Question 1

What is EtherChannel?

Answer 1

Bonding of multiple physical interfaces as a single logical interface.

i.e. LAG - Link Aggregate Group or ‘Port Channel’

Question 2

1. Recomended oversubscription ratio from the access layer to the distribution layer
2. Recomended oversubscription ratio from the distribution layer to the core layer

Answer 2

1. 20:1
2. 4:1

Question 3

In EtherChannel, what is a ‘flow’?

Answer 3

A traffic from a client to a server.

Can be setup to hash on:

1. MAC address (Layer 2 [L2])
2. IP address (Layer 3 [L3])
3. port number (Layer 4 [L4])

Question 4

What are the 3 EtherChannel Protocols?

Answer 4

1. LACP - Link Aggregation Control Protocol - Open Standard
2. PAgP - Port Aggregation Protocol - Cisco proprietary
3. Static EtherChannel - Manual config on each side of the link

Question 5

True or False?

Parameters on both sides of an EtherChannel link need to be setup the same?

Answer 5

True

1. Speed
2. Duplex
3. Access or Trunk Mode
4. Native VLAN on trunk ports
5. Access VLAN on access ports

Question 6

Interface Active/Passive combinations in LACP (EtherChannel) endpoints (3):

Answer 6

Passive / Passive - No Link

Active / Passive - LAG link comes up

Active / Active - LAG link comes up - This is best

Question 7

Interface Desirable/Auto combinations in PAgP (EtherChannel) endpoints (3):

Answer 7

Auto / Auto - No Link

Desirable / Auto- LAG link comes up

Desirable / Desirable - LAG link comes up - This is best

Question 8

Interface ‘On’ in Static combinations (EtherChannel) endpoints.

Answer 8

On / On - LAG link comes up

Question 9

How do you configure EtherChannel on a device?

Answer 9

SW1(config)# interface range f0/1 - 4
SW1(config-if-range)# channel-group 1 mode active SW1(config-if-range)# channel-group 1 mode desirable SW1(config-if-range)# channel-group 1 mode on

SW1(config)# interface port-channel 1
SW1(config-if)# switchport trunk encapsulation dot1q
SW1(config-if)# switchport mode trunk

Question 10

Command to view EtherChannel info

Answer 10

SW1# show etherchannel summary

Question 11

Command to view Spanning Tree config as it relates to EtherChannel:

Answer 11

SW1# show spanning-tree vlan 1

Question 12

What is StackWise as it relates to EtherChannel?

Answer 12

A form of Multi-Chassis EtherChannel.

Requires a high end multi-switch stack on one end of the link.
Supports full load balancing and redundancy.
Supported on some Catalyst switches.

Question 13

What is VSS as it relates to EtherChannel?

Answer 13

Virtual Switching System which is supported on some Catalyst switches.
A form of Multi-Chassis EtherChannel.

Question 14

What is vPC as it relates to EtherChannel?

Answer 14

Virtual Port Channel on Nexus switch family switches.
Switches are not part of a traditional “stack”, they are just seperate switches that talk to each other.