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17-5
Cisco ONS 15310-CL and Cisco ONS 15310-MA Ethernet Card Software Feature and Configuration Guide R8.5
78-18133-01
Chapter 17 CE-100T-8 Ethernet Operation
CE-100T-8 Ethernet Features
For an IP ToS-tagged packet, the CE-100T-8 can map any of the 256 priorities specified in IP ToS to
priority or best effort. The user can configure a different ToS on CTC at the card-level view under the
Provisioning > Ether Ports tabs. Any ToS class higher than the class specified in CTC is mapped to the
priority queue, which is the queue geared towards low latency. By default, the ToS is set to 255, which
is the highest ToS value. This results in all traffic being treated with equal priority by default.
Table 17-3 shows which values are mapped to the priority queue for sample IP ToS settings. (ToS
settings span the full 0 to 255 range, but only selected settings are shown.)
For a CoS-tagged frame, the CE-100T-8 can map the eight priorities specified in CoS to priority or best
effort. The user can configure a different CoS on CTC at the card-level view under the Provisioning >
Ether Ports tabs. Any CoS class higher than the class specified in CTC is mapped to the priority queue,
which is the queue geared towards low latency. By default, the CoS is set to 7, which is the highest CoS
value. This results in all traffic being treated with equal priority by default.
Table 17-2 shows which values are mapped to the priority queue for CoS settings.
Ethernet frames without VLAN tagging use ToS-based priority queueing if both ToS and CoS priority
queueing is active on the card. The CE-100T-8 card’s ToS setting must be lower than 255 (default) and
the CoS setting lower than 7 (default) for CoS and ToS priority queueing to be active. A ToS setting of
255 (default) disables ToS priority queueing, so in this case the CoS setting would be used.
Ethernet frames with VLAN tagging use CoS-based priority queueing if both ToS and CoS are active on
the card. The ToS setting is ignored. CoS based priority queueing is disabled if the CoS setting is the 7
(default), so in this case the ToS setting would be used.
Table 17-1 IP ToS Priority Queue Mappings
ToS Setting in CTC ToS Values Sent to Priority Queue
255 (default) None
250 251–255
150 151–255
100 101–255
50 51–255
0 1–255
Table 17-2 CoS Priority Queue Mappings
CoS Setting in CTC CoS Values Sent to Priority Queue
7 (default) none
67
56, 7
4 5, 6, 7
3 4, 5, 6, 7
2 3, 4, 5, 6, 7
1 2, 3, 4, 5, 6, 7
0 1, 2, 3, 4, 5, 6, 7