[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

How do the lowest layers of the DSL stack work?

Subject: How do the lowest layers of the DSL stack work?
From: stb at lassitu.de (Stefan Bethke)
Date: Mon, 2 Jul 2012 13:25:43 +0200
In-reply-to: <CAAWx_pU+txcudQowhMtQx8mhEBQVRhx6O_iQ6fx05Kvzh9otxA@mail.gmail.com>
References: <CAAWx_pU+txcudQowhMtQx8mhEBQVRhx6O_iQ6fx05Kvzh9otxA@mail.gmail.com>

Am 01.07.2012 um 21:01 schrieb James Bensley:

> [15.24 Mbit/s raw bit rate compared to 8.128 Mbit/s net] is quite a drop in speed and I'm trying to understand where this is happening.
...
> According to that extract, it all disappeared because of [Reed-Solomon] encoding, which is hugely vague.

http://en.wikipedia.org/wiki/Reed-Solomon_error_correction#Data_storage

The second paragraph explains that typically the raw bit rate is twice the net rate.

The raw bitstream is then encoded further as HDLC or ATM.


Stefan

-- 
Stefan Bethke <stb at lassitu.de>   Fon +49 151 14070811

References:
- How do the lowest layers of the DSL stack work?
  - From: jwbensley at gmail.com (James Bensley)

Prev by Date: NANOG Digest, Vol 54, Issue 3 (Comcast's IPv6 Information Site Unreachable)
Next by Date: FYI Netflix is down
Previous by thread: How do the lowest layers of the DSL stack work?
Next by thread: [c-nsp] NTP Servers
Index(es):
- Date
- Thread