HP Rx2620-2 - Integrity - 0 MB RAM Manual page 42

and all members in a particular team. This is accomplished by the Echo Node transmitting
a single Echo Node probe reply that is received by all teamed ports configured to monitor
the particular Echo Node. In contrast to Directed ARP, each individual teamed port is not
necessarily required to transmit its own Echo Node request, yet all teamed ports individually
receive an Echo Node probe reply.
With Community Address ARP, the team's Primary port transmits an Echo Node probe
request to the designated Echo Node. The Echo Node then transmits an Echo Node reply
that is received by every teamed port in that team. The Echo Node probe requests are sent
at the interval configured in the teaming GUI in the Echo Node Probe Interval field. After
the team's Primary port transmits an Echo Node probe request to the Echo Node, each
teamed port will wait for the number of Echo Node probe timeout seconds configured in
the teaming GUI. If for a particular teamed port, the Echo Node probe request times out
without receiving a response from the Echo Node, the teaming driver will assume the teamed
port does not have connectivity with the Echo Node and change the port state to Active
Path Failed. This prevents the port from being used as the Primary port in the team and will
prevent the team from using it as a Secondary (non-Primary) in load balancing teams (for
example, TLB). In addition, when the team detects connectivity problems with the Echo
Node for any teamed port, the team begins transmitting Echo Node requests on all ports in
the team. If the Primary port in a team loses connectivity with the Echo Node, another port
in the team with confirmed connectivity with the Echo Node will assume the role of Primary
(resulting in a failover).
For Community Address ARP, the Echo Node probe replies from the Echo Node are received
by every port in the team because of the special IP and MAC addresses configured in the
GUI. There are two additional configuration fields – Community Probe IP Address and
Community Probe MAC Address required for Community Address ARP. These addresses
are ONLY used for Echo Node purposes and are not used for data communication for the
team. These designated (by the server administrator) Community Address IP and MAC
addresses are used as the Source IP and MAC addresses in the Echo Node probe request
packets transmitted by teamed ports. The teamed ports transmit the Echo Node probe request
with their individual MAC address as the Source MAC address in the Ethernet header, but
use the Community Probe MAC address in the Source MAC Address ARP field. When the
Echo Node receives a Community Address ARP Echo Node probe request, the Echo Node
updates its ARP table with the Community Address IP and MAC addresses contained in
the Source MAC and IP ARP fields, not the Source MAC address from the Ethernet header.
The Echo Node then transmits a single Echo Node probe reply (in other words, ARP reply).
This Echo Node reply is sent using the information from the Echo Node's ARP table (in
other words, the Community Probe MAC address). All teamed ports have been configured
in hardware to receive on at least two unicast MAC addresses: the team's MAC address and
the configured Community Probe MAC address. Also, the teamed ports never transmit
using the configured Community Probe MAC address. As a result, none of the switches in
the LAN add the Community Probe MAC address to their MAC-to-port table (in other
words, MAC table or CAM table). This means that when the Echo Node sends an Echo Node
Reply destined to the MAC address defined as the Community Probe MAC address, all
switches in the network give a copy of the frame to every port. The result is that all teamed
ports configured to monitor connectivity with the Echo Node that transmitted the Echo
Node probe reply will receive the frame and validate connectivity – either within a single
team on a single server or across multiple teams on multiple servers if all are configured
with the same Community Probe IP/MAC and Echo Node. Network devices that aren't
configured to receive on the particular Community Probe MAC address will ignore the Echo
Node probe reply frame (dropped in hardware).
Community Address ARP's Echo Node Probe:
Much like Directed ARP's Echo Node probe, Community Address ARP also had to take
into account the same considerations:
42 The Mechanics of Teaming for the Advanced User