Schmid SHDSL - Ethernet over SHDSL

Watson-SHDSL-Router-Manual.doc
Version 1.0-03
Watson SHDSL Router
Operating Manual
3.5.3 Ethernet over SHDSL
Watson SHDSL router uses the Packet Transport Mode (PTM TPS-TC layer) of the ETSI TS 101
524 / ITU-T G.991.2 standards for transporting the Ethernet packets over the DSL wire pairs. As
encapsulation method HDLC and IEEE EFM 64b/65b framing are supported.
The HDLC packet encapsulation mode is used for connecting a Watson SHDSL router to a Watson
Ethernet plug-in (SZ.866.V654), which supports only the HDLC encapsulation mode.
DA SA
TCI ML/TL/T
DATA
Transmitted on DSL
stripped off before transmission over DSL
PRE Preamble
SFD Start-of-frame Delimiter
DA Destination address
SA Source address
L/T Length or type indicator = 802.1 QTagType
TCI Tag control information
ML/T MAC client length/type
DATA MAC client data
PAD Padding bytes
CRC Cyclic redundancy check sequence
generated before transmission over DSL
CRC-160x7E 0x7E
HDLC Framing (Flag character)
DA SA TCI
ML/T
L/T
DATA
MAC frame format with
IEEE 802.1p/q VLAN tags
CRC-32SFDPRE PAD
Figure 3-3: Ethernet over DSL with HDLC encapsulation
The EFM 64/65b framing mode is used when two Watson SHDSL routers are connected point-to-
point together or for connecting a Watson SHDSL router to another IEEE 802.3ah EFM compliant
device.
Figure 3-4: EFM fragmentation and framing
Revision: 2007-05-24 3-11