Vinay, SONET BLSR rings consist of four fibers and two full duplex paths, where the working path handles full duplex data, and the protect path sits idle. When the working path fails, the protect path (the other full duplex path) is activated, and handles full duplex data. -rb

From: Vinay Bannai <bannai@pacbell.net> Reply-To: bannai@pacbell.net To: Joao Takeda <joao_takeda@optiglobe.com.br> CC: "'nanog@merit.edu'" <nanog@merit.edu> Subject: Re: SONET and full duplex Date: Fri, 08 Jun 2001 10:58:27 -0700

Joao Takeda wrote:

...

Hi, ALL.

Can anyone confirm if links using SONET are full duplex? Thanks.

Takeda.

Sonet when deployed in rings tend to have dual rotating rings. Each ring carries traffic in a particular direction. Each node on the ring transmits on one of the rings and the other ring is used for receiving. However when using POS links which tend to point to point, then usually there are two fibers (one for transmitting and one for receiving). So to answer your question, most of the SONET links are full duplex.

Vinay

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