RE: IDLEs on the SONET line
Sorry for the confusion. You are correct. I forgot to include the word
my e-mail. Thus I should have said that the "average duration of the IPG for
to-back packets is 10.016026 nsec". As you say, the actual minimum IPG is
dependent on factors such as rate compensation.
From: Rich Taborek [mailto:rtaborek@xxxxxxxxxxxxx]
Sent: Saturday, September 30, 2000 4:34 PM
Subject: Re: IDLEs on the SONET line
I don't understand your calculation. The result (10.016026 ns) seems to
be the average LAN PHY IPG of 9.6 nsec divided by the WAN PHY data rate
of 9.58464 Gbps.
In my mind, the characteristics of idles to be put on the SONET line
after stripping some for rate control is:
a) an integer number of bytes;
b) has a minimum dependent on the minimum specified for the WAN PHY
primarily for clock rate compensation reasons and is typically dictated
by coding requirements as is the case for the LAN PHY where the minimum
transmitted IPG is 9 bytes and the minimum received IPG is 5 (???) bytes
(note: clock rate compensation is differentiated from MAC to WAN PHY
data rate compensation);
c) given an average IPG of 12 bytes, has an average duration of
Please tell me if I'm missing something.
>Tom Alexander wrote:
>Assuming back-to-back packets, the average IPG that will be present
>in the packet stream mapped to the SONET payload after deletion of
>idles will be 9.6 nsec. In the WAN-PHY application, the MAC will
>expand the IPG to lower the sustained data rate to < 9.58464 Gb/s while
>keeping the instantaneous data rate at 10.000 Gb/s. Effectively, this
>means that the minimum IPG will be increased to > 10.016026 nsec.
>When the PCS/WIS combination causes the extra idles to be
>deleted, this IPG will come back to 9.6 nsec.
>- Tom Alexander
>> Hi ALL,
>> This is regarding the number of IDLEs to be put on the
>> SONET line after stripping some for rate control.
>> What is the minimum IPG that must be there after deletion of idles?
>> Vinitha S
>> CoreEl Labs Pvt. Ltd
Richard Taborek Sr. Phone: 408-845-6102
Chief Technology Officer Cell: 408-832-3957
nSerial Corporation Fax: 408-845-6114
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