Service Manual

Creating a Layer 2 Class Map
All class maps are Layer 3 by default; however, you can create a Layer 2 class map by specifying the layer2 option with the
class-map command.
A Layer 2 class map dierentiates trac according to 802.1p value and/or VLAN and/or characteristics dened in a MAC ACL..
Use Step 1 or Step 2 to start creating a Layer 2 class map.
1. Create a match-any class map.
CONFIGURATION mode
class-map match-any
2. Create a match-all class map.
CONFIGURATION mode
class-map match-all
3. Specify your match criteria.
CLASS MAP mode
match mac
After you create a class-map, Dell Networking OS places you in CLASS MAP mode.
Match-any class maps allow up to ve access-lists. Match-all class-maps allow only one. You can match against only one VLAN
ID.
4. Link the class-map to a queue.
POLICY MAP mode
service-queue
Determining the Order in Which ACLs are Used to Classify Trac
When you link class-maps to queues using the service-queue command, Dell Networking OS matches the class-maps according
to queue priority (queue numbers closer to 0 have lower priorities).
For example, as described in the previous example, class-map cmap2 is matched against ingress packets before cmap1.
ACLs acl1 and acl2 have overlapping rules because the address range 20.1.1.0/24 is within 20.0.0.0/8. Therefore (without the
keyword order), packets within the range 20.1.1.0/24 match positive against cmap1 and are buered in queue 7, though you
intended for these packets to match positive against
cmap2 and be buered in queue 4.
In cases such as these, where class-maps with overlapping ACL rules are applied to dierent queues, use the keyword order. Dell
Networking OS writes to the CAM ACL rules with lower order numbers (order numbers closer to 0) before rules with higher order
numbers so that packets are matched as you intended.
• Specify the order in which you want to apply ACL rules using the keyword order.
order
The order can range from 0 to 254.
By default, all ACL rules have an order of 255.
Displaying Congured Class Maps and Match Criteria
To display all class-maps or a specic class map, use the following command.
Dell Networking OS Behavior: An explicit “deny any" rule in a Layer 3 ACL used in a (match any or match all) class-map creates a
"default to Queue 0" entry in the CAM, which causes unintended trac classication. In the following example, trac is classied in
two Queues, 1 and 2. Class-map ClassAF1 is “match any,” and ClassAF2 is “match all”.
• Display all class-maps or a specic class map.
Quality of Service (QoS)
591