Administrator Guide
Critical VLAN id: NONE
Mac-Auth-Bypass: Enable
Mac-Auth-Bypass Only: Disable
Static-MAB: Disable
Static-MAB Profile: NONE
Tx Period: 30 seconds
Quiet Period: 60 seconds
ReAuth Max: 2
Supplicant Timeout: 30 seconds
Server Timeout: 30 seconds
Re-Auth Interval: 3600 seconds
Max-EAP-Req: 2
Host Mode: SINGLE_HOST
Auth PAE State: Authenticated
Backend State: Idle
Dynamic CoS with 802.1X
Class of Service (CoS) is a method of traffic management that groups similar types of traffic so that they are serviced
differently. One way of classifying traffic is 802.1p, which uses the 3-bit Priority field in the VLAN tag to mark frames (other
classification methods include ToS, ACL, and DSCP). Once traffic is classified, you can use Quality of Service (QoS) traffic
management to control the level of service for a class in terms of bandwidth and delivery time.
For incoming traffic, the Dell Networking OS allows you to set a static priority value on a per-port basis or dynamically set a
priority on a per-port basis by leveraging 802.1X.
NOTE:
When a priority is statically configured using the dynamic dot1p command and dynamically configured using
dynamic CoS with 802.1X, the dynamic configuration takes precedence.
You can use dynamic CoS with 802.1X is when the traffic from a server should be classified based on the application that it is
running. A static dot1p priority configuration applied from the switch is not sufficient in this case, as the server application might
change. You would instead need to push the CoS configuration to the switches based on the application the server is running.
Dynamic CoS uses RADIUS attribute 59, called User-Priority-Table, to specify the priority value for incoming frames. Attribute
59 has an 8-octet field that maps the incoming dot1p values to new values; it is essentially a dot1p re-mapping table. The
position of each octet corresponds to a priority value: the first octet maps to incoming priority 0, the second octet maps to
incoming priority 1, etc. The value in each octet represents the corresponding new priority.
To use dynamic CoS with 802.1X authentication, no configuration command is required. You must only configure the supplicant
records on the RADIUS server, including VLAN assignment and CoS priority re-mapping table. VLAN and priority values are
automatically applied to incoming packets. The RADIUS server finds the appropriate record based on the supplicant’s credentials
and sends the priority re-mapping table to the Dell Networking system by including Attribute 59 in the AUTH-ACCEPT packet.
The following conditions apply to the use of dynamic CoS with 802.1X authentication on the switch:
● In accordance with port-based QoS, incoming dot1p values can be mapped to only four priority values: 0, 2, 4, and 6. If the
RADIUS server returns any other dot1p value (1, 3, 5, or 7), the value is not used and frames are forwarded on egress queue
0 without changing the incoming dot1p value. The example shows how dynamic CoS remaps (or does not remap) the dot1p
priority in 802.1X-authenticated traffic and how the frames are forwarded:
Incoming Frame RADIUS-based Outgoing Frame Egress Queue
Tagged dot1p CoS Remap Table Tagged dot1p
-------------- --------------- -------------- ------------
0 7 0 0
1 5 1 0
2 4 4 2
3 6 6 3
4 3 4 0
5 1 5 0
6 2 2 0
7 4 4 2
● The priority of untagged packets is assigned according to the remapped value of priority 0 traffic in the RADIUS-based table.
For example, in the following remapping table, untagged packets are tagged with priority 2:
Dell#show dot1x cos-mapping interface TenGigabitethernet 2/3
802.1Xp CoS remap table on Te 2/3:
-----------------------------
104
802.1X