Feral Packet

v5 Written:
2.1.e Implement and troubleshoot EtherChannel
2.1.e [i] LACP PAgP, manual
2.1.e [ii] Layer 2, Layer 3
2.1.e [iii] Load-balancing
2.1.e [iv] Etherchannel misconfiguration guard

v5 Lab:
1.1.e Implement and troubleshoot etherchannel
1.1.e [i] LACP, PAgP, manual
1.1.e [ii] layer 2, layer 3
1.1.e [iii] load-balancing
1.1.e [iv] etherchannel misconfiguration guard

Documentation:

Catalyst 3750-X and 3560-X Software Configuration Guide, Release 15.0(1)SE,
Chapter 40: Configuring EtherChannels and Link-State Tracking, pgs. 40-1 to 40-25

Books:

CCIE Routing and Switching Exam Certification Guide 4th Ed; Chapter 3: Spanning Tree Protocol, PortChannels, pgs. 82 – 84, 98 – 99

Cisco LAN Switching; Chapter 8: Trunking Technologies and Applications,
EtherChannel, pgs. 298 – 306

INE:

EtherChannel provides fault-tolerant high-speed links between switches, routers, and servers.
– used to increase bandwidth
– provides automatic recovery from the loss of a link
– consists of individual Gigabit Ethernet links bundled into a single logical link
– provides full-duplex bandwidth up to 8Gb/s or 80Gb/s
– consist of up to eight compatibly configured Ethernet ports
– layer 2 or layer 3
– the number of EtherChannels is limited to 48

Layer 3 EtherChannels are not supported on switches running the LAN base feature set

EtherChannel modes
– Port Aggregation Protocol (PAgP)
– Link Aggregation Protocol (LACP)
– On

Each EtherChannel has a port-channel logical interface
– numbered 1 to 48
– with Layer 2 interfaces, the channel-group interface command dynamically creates the port-channel logical interface
– with Layer 3 interfaces, the logical interface must be created manually
– after configuring EtherChannel, any changes made to the logical interface is applied to all of the physical ports

PAgP is a Cisco proprietary protocol
– DTP and CDP send and receive packets over the physical ports in the EtherChannel
– for Layer 2, the first port in the channel provides the MAC address for the EtherChannel
– for Layer 3, the switch allocates a MAC address when the logical interface is created
– trunk ports send and receive PAgP packets on the lowest numbered VLAN

PAgP ports must all have the same configuration
– speed
– duplex
– VLAN
– native VLAN
– trunking status
– type

PAgP adds the logical interface to spanning tree as a single interface

PAgP modes
– auto
– desirable

PAgP auto
– places port in a passive negotiating state
– port responds to PAgP packets
– does not start PAgP packet negotiation

PAgP desirable
– places port into an active negotiating state
– starts negotiations with other ports

LACP
– defined by IEEE 802.3ad
– DTP and CDP send and receive packets over the physical ports in the EtherChannel
– trunk ports send and receive LACP packets on the lowest numbered VLAN
– for Layer 2, the first port in the channel provides the MAC address for the EtherChannel
– for Layer 3, the switch allocates a MAC address when the logical interface is created

LACP modes
– active
– passive

LACP active
– places port into an active negotiating state
– start negotiations with other ports

LACP passive
– places port in a passive negotiating state
– port responds to LACP packets
– does not start LACP packet negotiation

EtherChannel On Mode
– used to manually configure an EtherChannel
– forces a port to join an EtherChannel without negotiations
– can be useful if the remote device does not support PAgP or LACP
– all ports must be configured the same
– if the EtherChannel group is misconfigured, packet loss or spanning tree loops can occur

Load balancing
– dst-ip
– dst-mac
– src-dst-ip
– src-dst-mac
– src-ip
– src-mac

Default EtherChannel configuration
– channel-groups: none assigned
– port-channel logical interface: none defined
– PAgP mode: no default
– PAgP learn method: aggregate-port learning on all ports
– LACP mode: no default
– LACP learn method: aggregate-port on all ports
– LACP port priority: 32768 on all ports
– LACP system priority: 32768
– LACP system ID: LACP system priority and the switch MAC address
– load-balancing: src-mac

EtherChannel configuration guidelines
– if improperly configured, some EtherChannel ports are automatically disabled to avoid network loops or other problems
– no more than 48 EtherChannels
– up to 8 ports for PAgP
– up to 16 ports for LACP, 8 ports are active, 8 ports are in standby mode
– configure all ports for the same speed and duplex
– do not configure with a SPAN destination port
– do not configure with a secure port
– do not configure with a private VLAN
– do not configure with 802.1X
– do not enable link-state tracking

conf t
int gi0/1
switchport mode { access | trunk }
switchport access vlan
channel-group mode {auto [non-silent]|desirable [non-silent]|on}|{active|passive}

conf t
int po1
no switchport
ip address
int gi0/1
no switchport
no ip address
channel-group mode {auto [non-silent]|desirable [non-silent]|on}|{active|passive}

conf t
port-channel load-balance {dst-ip|dst-mac|src-dst-ip|src-dst-mac|src-ip|src-mac}

show etherchannel load-balance
show pagp internal
show pagp counters
show pagp neighbor
show lacp sys-id
show lacp counters
show lacp internal
show lacp neighbor
show etherchannel detail
show etherchannel summary