342-86400-498PS
Issue 1.2
April 2012
Page 97
Copyright
GE Multilin Inc. 2010-2012
The unit encapsulates the assigned mapping priority into the
Envelope Header
(attached to each frame for transmission between ETHER-1000 units) to be used
for priority queue selections at the local ETHER-1000 unit and all other ETHER-
1000 units along the frame‟s path. The Envelope Header is removed at the
destination ETHER-1000 unit's GMII port before the frame is passed onto its
local paddleboard for dropping; however, the mapping priority is passed along
with the frame by other means so that it can be used for priority queue selections
at the destination “LAN” switch.
The ETHER-
1000 unit (the “WAN” switch) has 16 priority queues (8 for “add”
traffic and 8 for “pass-through” traffic) for each TDM pipe on either Line port. The
unit also has 8 priority queues for the “drop” traffic associated with the GMII port
(the port facing paddleboard).
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The highest priority queue (within each set of 8)
is reserved for “EtherType traffic”
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, while the 7 lower priority queues are used for
all other traffic, based on individual frames‟ mapping priorities.
Note:
The frames being forwarded from the “LAN” to the “WAN” switch are
competing for the GMII port‟s “add” bandwidth (1 Gbps) based on their
EtherType / source priority designation. The frames being forwarded from the
“WAN” to the “LAN” switch are competing for the GMII port‟s “drop” bandwidth (1
Gbps) based on their mapping priority designation.
Note
: An 802.1p/Q tagged frame transported across the ETHER-1000 system
may have its source 3-bit priority value carried in the tag modified at egress.
More specifically, an egressing tagged frame will have its priority set to N if its
respective source port‟s Mapping Priority is set to “Priority N” (N=1…6) while this
priority will be set to 7 if the frame was segregated as a “super-priority” frame
using EtherType filtering feature at the source port. Note that the 802.1Q tag's
VLAN ID is not affected. Note that this will happen on any other product using
the same Marvell switch chip.
EtherType
Possible selections are: „IEC 61850 (GOOSE)‟ (default), „IEC 61850
(GSE)‟, „IEC 61850 (SV)‟ and „IEEE 1588: PTP‟.
All ingress frames whose EtherType is matching the EtherType
selected in this field will use the highest priority queues in both
paddleboard (“LAN”) and ETHER-1000 (“WAN”) switches regardless of
the settings in the Source and Mapping fields.
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The Top port (i.e. the Ethernet port residing on the top of ETHER-1000 unit) is unused and
therefore not mentioned here.
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In addition to ETHER-
1000 system “maintenance traffic”, which is very minimal.