Cisco Catalyst 4500 series Administration Manual page 968

VRF-lite Configuration Guidelines
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IPv4 Specific
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IPv6 specific
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Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
41-4
VRF-lite lets multiple customers share the same physical link between the PE and the CE. Trunk
ports with multiple VLANs separate packets among customers. All customers have their own
VLANs.
VRF-lite does not support all MPLS-VRF functionality: label exchange, LDP adjacency, or labeled
packets.
For the PE router, there is no difference between using VRF-lite or using multiple CEs. In
Figure 41-1, multiple virtual Layer 3 interfaces are connected to the VRF-lite device.
The Catalyst 4500 series switch supports configuring VRF by using physical ports, VLAN SVIs, or
a combination of both. You can connect SVIs through an access port or a trunk port.
A customer can use multiple VLANs as long because they do not overlap with those of other
customers. A customer's VLANs are mapped to a specific routing table ID that is used to identify
the appropriate routing tables stored on the switch.
The Layer 3 TCAM resource is shared between all VRFs. To ensure that any one VRF has sufficient
CAM space, use the maximum routes command.
A Catalyst 4500 series switch using VRF can support one global network and up to 64 VRFs. The
total number of routes supported is limited by the size of the TCAM.
A single VRF can be configured for both IPv4 and IPv6.
PBR and VRF cannot be configured on the same interface. Similarly, WCCP, Etherchannel and MEC
cannot be configured on the same interface with VRF.
If an incoming packet's destination address is not found in the vrf table, the packet is dropped. Also,
if insufficient TCAM space exists for a VRF route, hardware switching for that VRF is disabled and
the corresponding data packets are sent to software for processing.
You can use most routing protocols (BGP, OSPF, EIGRP, RIP and static routing) between the CE
and the PE. However, we recommend using external BGP (EBGP) for these reasons:
– BGP does not require multiple algorithms to communicate with multiple CEs.
– BGP is designed for passing routing information between systems run by different
administrations.
– BGP makes simplifies passing attributes of the routes to the CE.
VRF-lite does not support IGRP and ISIS.
Beginning with Cisco IOS Release 12.2(50)SG, Multicast and VRF can be configured together on a
Layer 3 interface.
The Catalyst 4500 series switch supports all the PIM protocols (PIM-SM, PIM-DM, PIM-SSM, PIM
BiDIR).
The capability vrf-lite subcommand under router ospf should be used when configuring OSPF as
the routing protocol between the PE and the CE.
VRF-aware OSPFv3, BGPv6, EIGRPv6, and IPv6 static routing are supported.
VRF aware ISISv6, RIPng, IPv6 Multicast Routing(MVRF), and PIMv6 are not supported.
VRF-aware IPv6 route applications include: ping, telnet, ssh, tftp, ftp and traceroute. (This list does
not include the Mgt interface, which is handled differently even though you can configure both IPv4
or IPv6 VRF under it.)
Chapter 41 Configuring VRF-lite
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