Table Of Contents
Layer 2 Access Control Lists on EVCs
Prerequisites for Layer 2 Access Control Lists on EVCs
Restrictions for Layer 2 Access Control Lists on EVCs
Information About Layer 2 Access Control Lists on EVCs
Relationship Between ACLs and Ethernet Infrastructure
How to Configure Layer 2 Access Control Lists on EVCs
Applying a Layer 2 ACL to a Service Instance
Configuring a Layer 2 ACL with ACEs on a Service Instance
Verifying the Presence of a Layer 2 ACL on a Service Instance
Configuration Examples for Layer 2 Access Control Lists on EVCs
Example: Creating a Layer 2 ACL with ACEs
Example: Applying a Layer 2 ACL to a Service Instance
Example: Applying a Layer 2 ACL to Three Service Instances on the Same Interface
Example: Displaying the Details of a Layer 2 ACL on a Service Instance
Feature Information for Layer 2 Access Control Lists on EVCs
Layer 2 Access Control Lists on EVCs
First Published: October 24, 2008Last Updated: February 7, 2011The ability to filter packets in a modular and scalable way is important for both network security and network management. Access Control Lists (ACLs) provide the capability to filter packets at a fine granularity. In Metro Ethernet networks, ACLs are directly applied on Ethernet virtual circuits (EVCs).
Layer 2 Access Control Lists on EVCs is a security feature that allows packet filtering based on MAC addresses. This module describes how to implement ACLs on EVCs.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for Layer 2 Access Control Lists on EVCs" section.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
•Prerequisites for Layer 2 Access Control Lists on EVCs
•Restrictions for Layer 2 Access Control Lists on EVCs
•Information About Layer 2 Access Control Lists on EVCs
•How to Configure Layer 2 Access Control Lists on EVCs
•Configuration Examples for Layer 2 Access Control Lists on EVCs
•Feature Information for Layer 2 Access Control Lists on EVCs
Prerequisites for Layer 2 Access Control Lists on EVCs
•Knowledge of how service instances must be configured.
•Knowledge of extended MAC ACLs and how they must be configured.
Restrictions for Layer 2 Access Control Lists on EVCs
•A maximum of 16 access control entries (ACEs) are allowed for a given ACL.
•Only 256 different or unique Layer 2 ACLs can be configured on a line card. (More than 256 ACLs can be configured on a router.)
•Layer 2 ACLs function inbound only.
•Current Layer 2 ACLs provide Layer 3 filtering options in permit and deny rules. Options that are not relevant to service instances are ignored.
Information About Layer 2 Access Control Lists on EVCs
•EVC
•Relationship Between ACLs and Ethernet Infrastructure
EVC
An EVC as defined by the Metro Ethernet Forum is a port-level point-to-point or multipoint-to-multipoint Layer 2 circuit. It is an end-to-end representation of a single instance of a Layer 2 service being offered by a provider to a customer. It embodies the different parameters on which the service is being offered. A service instance is the instantiation of an EVC on a given port on a given router.
Ethernet virtual connection services (EVCS) uses EVCs and service instances to provide Layer 2 switched Ethernet services. The EVC status can be used by a customer edge (CE) device either to find an alternative path in to the service provider network or, in some cases, to revert to a backup path over Ethernet or over another alternative service such as Frame Relay or ATM.
For information about the Metro Ethernet Forum standards, see the "Standards" section.
Relationship Between ACLs and Ethernet Infrastructure
The following points capture the relationship between ACLs and Ethernet Infrastructure (EI):
•ACLs can be directly applied on an EVC using the command-line interface (CLI). An ACL is applied to a service instance, which is the instantiation of an EVC on a given port.
•One ACL can be applied to more than one service instance at any time.
•One service instance can have one ACL at most applied to it at any time. If a Layer 2 ACL is applied to a service instance that already has a Layer 2 ACL, the new one replaces the old one.
•Only named ACLs can be applied to service instances. The command syntax ACLs is retained; the mac access-list extended command is used to create an ACL.
•The show ethernet service instance command can be used to provide details about ACLs on service instances.
How to Configure Layer 2 Access Control Lists on EVCs
•Applying a Layer 2 ACL to a Service Instance
•Configuring a Layer 2 ACL with ACEs on a Service Instance
•Verifying the Presence of a Layer 2 ACL on a Service Instance
Creating a Layer 2 ACL
Perform this task to create a Layer 2 ACL with a single ACE.
SUMMARY STEPS
1. enable
2. configure terminal
3. mac access-list extended name
4. permit {{src-mac mask | any} {dest-mac mask | any} [protocol [vlan vlan] [cos value]]}
DETAILED STEPS
Applying a Layer 2 ACL to a Service Instance
Perform this task to apply a Layer 2 ACL to a service instance. Note that packet filtering takes place only after the ACL has been created and applied to the service instance.
Prerequisites
Before applying an ACL to a service instance, you must create it using the mac access-list extended command. See the "Creating a Layer 2 ACL" section.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface type number
4. service instance id ethernet
5. encapsulation dot1q vlan-id
6. mac access-group access-list-name in
DETAILED STEPS
Configuring a Layer 2 ACL with ACEs on a Service Instance
Perform this task to configure the same ACL with three ACEs and stop all other traffic on a service instance.
SUMMARY STEPS
1. enable
2. configure terminal
3. mac access-list extended name
4. permit {src-mac mask | any} {dest-mac mask | any}
5. permit {src-mac mask | any} {dest-mac mask | any}
6. permit {src-mac mask | any} {dest-mac mask | any}
7. deny any any
8. exit
9. interface type number
10. service instance id ethernet
11. encapsulation dot1q vlan-id
12. mac access-group access-list-name in
DETAILED STEPS
Verifying the Presence of a Layer 2 ACL on a Service Instance
Perform this task to verify that a Layer 2 ACL is present on an EVC. This verification task can be used after an ACL has been configured to confirm its presence.
SUMMARY STEPS
1. enable
2. configure terminal
3. show ethernet service instance id id interface type number detail
DETAILED STEPS
Configuration Examples for Layer 2 Access Control Lists on EVCs
•Example: Creating a Layer 2 ACL with ACEs
•Example: Applying a Layer 2 ACL to a Service Instance
•Example: Applying a Layer 2 ACL to Three Service Instances on the Same Interface
•Example: Displaying the Details of a Layer 2 ACL on a Service Instance
Example: Creating a Layer 2 ACL with ACEs
The following example shows how to create a Layer 2 ACL called mac-11-acl with two permitted ACEs:
enableconfigure terminalmac access-list extended mac-11-aclpermit 00aa.00bb.00cc 1a11.0101.11c1 anypermit 00aa.00bb.00cc 1a11.0101.11c2 anyExample: Applying a Layer 2 ACL to a Service Instance
The following example shows how to apply a Layer 2 ACL called mac-20-acl to a service instance. The ACL has five permitted ACEs and all other traffic is not allowed.
enableconfigure terminalmac access-list extended mac-20-aclpermit 00aa.bbcc.adec 0.0.0 any
permit 00aa.bbcc.bdec 0.0.0 any
permit 00aa.bbcc.cdec 0.0.0 any
permit 00aa.bbcc.edec 0.0.0 any
permit 00aa.bbcc.fdec 0.0.0 any
deny any anyexitinterface gigabitethernet 10/0/0service instance 100 ethernetencapsulation dot1q 100mac access-group mac-20-acl inExample: Applying a Layer 2 ACL to Three Service Instances on the Same Interface
The following example shows how to apply a Layer 2 ACL called mac-07-acl to three service instances on the same interface:
enableconfigure terminalmac access-list extended mac-07-aclpermit 00aa.bbcc.adec 0.0.0 any
permit 00aa.bbcc.bdec 0.0.0 any
permit 00aa.bbcc.cdec 0.0.0 any
deny any anyexitinterface gigabitethernet 10/0/0service instance 100 ethernetencapsulation dot1q 100mac access-group mac-07-acl inservice instance 101 ethernetencapsulation dot1q 101mac access-group mac-07-acl inservice instance 102 ethernetencapsulation dot1q 102mac access-group mac-07-acl inExample: Displaying the Details of a Layer 2 ACL on a Service Instance
The following sample output displays the details of a Layer 2 ACL called test-acl on a service instance.
Router# show ethernet service instance id 100 interface ethernet0/0 detailService Instance ID: 100L2 ACL (inbound): test-aclAssociated Interface: Ethernet0/0Associated EVC: testL2protocol dropCEVlans:Interface Dot1q Tunnel Ethertype: 0x8100State: UpL2 ACL permit count: 10255L2 ACL deny count: 53Table 1 describes the significant fields in the output.
Additional References
Related Documents
Standards
Standard TitleMEF 6.1
Metro Ethernet Services Definitions Phase 2 (PDF 6/08)
MEF 10.1
Ethernet Services Attributes Phase 2 (PDF 10/06)
MIBs
MIB MIBs Link•None
To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:
RFCs
Technical Assistance
Feature Information for Layer 2 Access Control Lists on EVCs
Table 2 lists the release history for this feature.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note Table 2 lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
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