From: NotariE@usa.redcross.org
Date: Wed Sep 05 2007 - 07:59:56 EDT
Hello Alpha Managers,
We have installed and configured two (2) GBit NICs in our ES40 to use
LAG. Specifically, they are using the "load distribution algorithm"
defined as "dstip". (See options below)
I am new at using LAG and would like your opinion on which algorithm
would be best for my environment.
We are running SAS on the ES40 (Tru64 v5.1b) with 4 local X-Clients
connecting (same VLAN) and 3 external X-Clients connecting (intranet).
Each of these clients will have, from time-to-time, large files to FTP
to/from their local systems. Storage is not an issue and memory is maxed
out. Security is quite high, SSH2, and other AISSP implementations.
Any thoughts and opinions would be welcomed.
As an aside;
The Network Operations folks have offered to "bind" the ports on the
switch if I should require it. From what I can tell, LAG does not
require this. Is there a good reason to use bound switch ports? Is
that something that Netrain uses?
Thanks,
Ed Notari
=================================================================
>From Tru64 MAN Page for LAG
Destination IP Address (dstip)
For IP packets, the port is selected based on a hash of the
destination
IP address. For non-IP packets, the port is selected based on a
hash
of the destination MAC address. All traffic addressed to a
specific
destination IP address uses the same port in the link aggregation
group.
This algorithm can utilize the combined bandwidth of a link
aggregation
group in environments where traffic is destined to a large number
of
different IP addresses (for example, a web server).
However, this algorithm might not produce the expected bandwidth
utili-
zation in environments where the majority of traffic is destined
to a
single IP address (for example, a private server-to-server
intercon-
nect).
Destination MAC address (dstmac)
The port is selected based on a hash of the destination MAC
address.
All traffic addressed to a specific destination MAC address uses
the
same port in the link aggregation group.
This algorithm can utilize the combined bandwidth of a link
aggregation
group in environments where traffic is destined to a large number
of
different MAC addresses (for example, a server that sends most of
its
traffic to clients on the same LAN).
However, this algorithm might not produce the expected bandwidth
utili-
zation in environments where the majority of traffic is destined
to a
small number of MAC addresses (for example, a server-to-server
inter-
connect, or a server that sends most of its traffic through a
router).
Transport Port number (port)
For TCP or UDP packets originating on the system, the port is
selected
based on a hash of the source and destination TCP or UDP port
numbers.
For all other packets, including TCP and UDP packets being
forwarded by
the system, the Destination IP address (dstip) algorithm is used.
All
traffic addressed to a specific source+destination port pair uses
the
same port in the link aggregation group.
This algorithm can utilize the combined bandwidth of a link
aggregation
group in environments where traffic is destined to a single IP or
MAC
address, but is exchanged between a number of different TCP or UDP
port
number pairs (for example, a server-to-server interconnect).
Round Robin (roundrobin)
The port is selected on a rotating basis.
This algorithm can utilize the combined bandwidth of a link
aggregation
group in most environments.
However, this algorithm may result in reordering of packets
belonging
to the same flow (for example, a TCP connection), which in turn
may
adversely affect performance.
=================================================================
"Do not go gentle into that good night,
Old age should burn and rave at close of day;
Rage, rage against the dying of the light." - Dylan Thomas
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