chapter 3

Question 1

what is EtherChannel? how does it work?

Answer 1

several Ethernet ports are bundled together to act as one logical connection called a port channel. allows a less expensive switch to provide more bandwidth.

Question 2

PAgP?

Answer 2

Port Aggregation Protocol:

Question 3

PAgP?

Answer 3

Port Aggregation Protocol: cisco proprietary used on switches to negotiate and determine the configuration of each side of a connection, then decides if they are compatible, before Etherchannel link is enabled.

Question 4

how are EtherChannels formed?

Answer 4

dynamic negotiation using protocols: PAgP or LACP. ports with similar characteristics are able to form an EtherChannel between 2 switches.

Question 5

what are (PAgP modes)?

Answer 5

a connection on each side has a port that is configured with a certain mode. the modes auto-negotiate to determine if a channel can form. there are 3 types of modes.

Question 6

PAgP mode ON?

Answer 6

interface is forced into EtherChannel without using PAgP packets.

Question 7

PAgP mode DESIRABLE?

Answer 7

the port actively negotiates with other interfaces by sending PAgP packets.

Question 8

PAgP mode AUTO?

Answer 8

this port will not initiate PAgP negotiation packets but it will reply to PAgP packets to form an EtherChannel.

Question 9

LACP?

Answer 9

Link Aggregation Control Protocol.

Question 10

what is LACP?

Answer 10

Link Aggregation Control Protocol: IEEE used to facilitate EtherChannels in multi vendor environments. several ethernet channels are bundled to form one logical link (EtherChannel)

Question 11

LACP mode passive?

Answer 11

the port is in a passive negotiate state and does not send out LACP negotiation packets. it will respond to Link Aggregation Control Protocols that it receives.

Question 12

LACP mode active?

Answer 12

the port actively sends out LACP packets to other switch ports asking them for a connection so an EtherChannel can be made.

Question 13

LACP mode on?

Answer 13

EtherChannel is forced without the use of LACP. no LACP packets are exchanged from this port.

Question 14

what must be the same on both ends of an interface for an EtherChannel to form? also these settings must be the same between all interfaces that make up the EtherChannel.

Answer 14

port speed, duplex (half or full) and vlan that they belong to must be the same.
**can support several vlans if the Port channels are configured as a trunk. the vlans supported must be the same on both ends of the trunk.

Question 15

Which command displays only one line of information per port channel?

Answer 15

show etherChannel summary

Question 16

Which three interface parameters must match for an EtherChannel to form?

Answer 16

allowed VLANs
native VLAN
trunking mode

Question 17

What are three advantages of using EtherChannel technology

Answer 17

Configuration tasks can be done on the EtherChannel interface.

There is no need to upgrade links to faster connections to increase bandwidth.

A spanning tree recalculation is not required when a single link within the channel goes down.

Question 18

how many ports can LACP be configured on to form one logical link?

Answer 18

16. 8 are active and 8 are in standby for when/if one of the active link fails.