1. Manuals
  2. Brands
  3. Computer Equipment
  4. Switch
  5. IBM
  6. Computer Equipment
  7. Switch

IBM 12.1(22)EA6 Physical Learners and Aggregate-Port Learners, PAgP and LACP Interaction with Other Features

1 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 550
Download on canonical page 550 pages, 5.74 Mb
24-5
Cisco Systems IntelligentGigabit Ethernet Switch Modules for the IBM BladeCenter, Software Configuration Guide
24R9746
Chapter24 Configuring EtherChann els and Layer 2 Trunk Failover
Understanding EtherChannels

Exchanging LACP Packets

Both the active and passive LACP modes allow interfaces to negotiate with partner interfaces to
determine if they can form an EtherChannel based on criteria such as interface speed and, for Layer2
EtherChannels, trunking state, and VLAN numbers.
Interfaces can form an EtherChannel when they are in different LACP modes as long as the modes are
compatible. For example:
•An interface in the active mode can form an EtherChannel with another interface that is in the active
mode.
•An interface in the active mode can form an EtherChannel with another interface in the passive
mode.
An interface in the passive mode cannot form an EtherChannel wit h another interface that is also in the
passive mode because neither interface starts LACP negotiation.
Note An EtherChannel cannot be configured in both the PAgP and LACP modes.
Physical Learners and Aggregate-Port Learners
Network devices are classified as PAgP physical learners or aggregate-port learners. A device is a
physical learner if it learns addresses by physical ports and directs transmissi ons based on that
knowledge. A device is an aggregate-port learner if it learns addresses by aggregate (logical) ports.
When a device and its partner are both aggregate-port learners, they learn the address on the logical
port-channel. The device sends packets to the source by using any of the interface s in the EtherChannel.
With aggregate-port learning, it is not important on whi ch physical port the packet arrives.
The switch uses source-MAC address distribution for a channel if it is connected to a physical learner
even if you configure the switch for destination-MAC address distribution.
These frame distribution mechanisms are possible for frame transmission:
•Load distribution based on the source-MAC address of the packet
•Load distribution based on the destination-MAC address of the packet
•Load distribution based on the XOR of the source-MAC address and destina tion-MAC address
•Load distribution based on the source-host IP address
•Load distribution based on the destination-host IP address
•Load distribution based on the XOR of the source-IP address and destination-IP address
The switch supports up to eight ports in a PAgP group.
PAgP and LACP Interaction with Other Features
The Dynamic Trunking Protocol (DTP) and Cisco Discovery Protocol (CDP) send and receive packets
over the physical interfaces in the EtherChannel. Trunk ports send and receive PAgP and LACP protocol
data units (PDUs) on the lowest numbered VLAN.
Spanning tree sends packets over a single physical interface in the EtherChanne l, regarding the
EtherChannel as one port.
MENU

Models

Contents