Subject: duplex full vs half

From: "Debby Stopp" <[email-masked]>
Date: Fri, 18 Jun 1999 14:12:42 -0700

I've noticed that the following paragraph is used on the majority of tests:

      In half duplex mode, exactly half of the intended load SHOULD be
      transmitted to each of the ports under test. For example, with a
      100% load of 64-byte frames, the intended load for each port under
      test is 7440 frames received per second and 7440 frames
      transmitted per second (for 10Mbps Ethernet).

I think that a little more discretion should be exercised w/this statement,
ie., transmit rate should be based on whether the Rx ports are also Tx ports
& vice/versa, such as in a fully meshed configuration vs.  the partially
meshed configuration where TX ports do not receive & RX ports do not
transmit.

In other words, for the uni-directional tests, I don't see any reason to
half my transmit rate.  If my phy is capable of transmitting at full line
rate, albeit half duplex, than I should be testing my phy at full line rate
regardless of the duplex mode.

I suggest that this paragraph be removed from those test configurations that
are defined as uni-directional (ie., partially meshed, Multiple streams of
unidirectional traffic, filter illegal frames, & broadcast frame handling
and latency test ) & that it should be quantified for the others.

For example:
      When testing a bidirectional many-to-one or one-to-many configuration
      in half duplex mode, exactly half of the intended load SHOULD be
      transmitted to each of the ports under test. For example, with a
      100% load of 64-byte frames, the intended load for each port under
      test is 7440 frames received per second and 7440 frames
      transmitted per second (for 10Mbps Ethernet).

and this paragraph becomes redundant.
>>>   In full duplex mode, the entire intended load SHOULD be
      transmitted to each of the ports under test. For example, with a
      100% load of 64-byte frames, the intended load for each port under
      test is 14880 frames received per second and 14880 frames
      transmitted per second (for 10Mbps Ethernet).

Debby Stopp
Ixia Communications
[email-masked]