Subject: [Hubmib] ifHighSpeed in draft-ietf-hubmib-etherif-mib-v3-00.txt

From: "C. M. Heard" <[email-masked]>
Date: Sat, 21 Jul 2001 14:12:25 -0700 (PDT)

Greetings,

The current etherif-v3 draft states that ifHighSpeed shall be
"equal to 10,000 for LAN implentations [sic] of 10 Gb/s, and
9,585 for WAN implementations of the 10 Gb/s MAC over an
OC-192 PHY."

Traditionally, ifSpeed and ifHighSpeed have represented the data
rate before PCS encoding on transmit and after PCS decoding on
receive.  If I correctly understand what I have read, that's
still the case for 10 Gb/s LAN implementations:  the raw data
rate when using 64B/66B encoding is 10.3125 Gb/s, and the raw
data rate when using 8B/10B encoding is 12.5 Gb/s.  In view of
that, it would seen that the proper ifHighSpeed value to use
for WAN implementations is not 9585 Mb/s, which is the data
rate of the OC-192c payload after 64B/66B encoding or prior to
64B/66B decoding, but rather is 9294 Mb/sec, which is the data rate
at the reconciliation sublayer prior to encoding or after decoding.

Mike

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