Egress EFP Filtering
The Egress EFP Filtering feature implements a means of filtering EFP egress traffic, ensuring that all the
given EFP’s egress traffic complies with the ingress matching criterion.
An ingress EFP is similar to an egress EFP. The router is configured to send traffic on the EFP, that matches
that EFP’s ingress matching criterion. It is possible to configure a router so that this does not occur, and there
is no safeguard to prevent such mismatching egress EFP traffic from exiting the router.
The Cisco ASR 9000 Series Routers allow for different VLANs on different ports within the same bridge
domain. This allows a bridge to forward a packet out of a port not configured for the VLAN tag on the packet.
Egress EFP filtering checks this and drops invalid packets at the egress port.
Identifying Frames of an EFP
The EFP identifies frames belonging to a particular flow on a given port, independent of their Ethernet
encapsulation. An EFP can flexibly map frames into a flow or EFP based on the fields in the frame header.
The frames can be matched to an EFP using:
• VLAN tag or tags
• MAC address (source address, destination address, or both)
• 802.1p CoS bits
• Logical conjunction of two or more of the above: VLAN, MAC, and CoS
• Default match (that is, any other traffic that has not matched a more specific EFP)
• Protocol ethertype
The frames cannot be matched to an EFP through use of any of these:
• Any information outside the outermost Ethernet frame header and its associated tags such as
• IPv4, IPv6, or MPLS tag header data
• C-DMAC, C-SMAC, or C-VLAN
• Logical disjunction of the valid frame matches above: VLAN, MAC, and CoS
The specific match criteria are covered in more detail in these sections.
VLAN Tag Matching
Below table describes the different encapsulation types and the EFP identifier corresponding to each.
EFP IdentifierEncapsulation Type
Static configuration on the ingress physical interface
or a subinterface that uses the untagged keyword in
the encapsulation command. There can be only one
untagged subinterface. If an untagged subinterface
has been created, traffic goes to this interface instead
of the main interface.
Untagged
L2VPN and Ethernet Services Configuration Guide for Cisco ASR 9000 Series Routers, IOS XR Release 6.3.x
15
The Carrier Ethernet Model
Egress EFP Filtering
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