© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Implementation of Frame Mode MPLS Implementing Frame Mode MPLS

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v The Procedure to Configure MPLS

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v The Procedure to Configure MPLS 1. Configure CEF 2. Configure MPLS on a frame mode interface 3.(Optional) Configure the MTU size in label switching

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Configuring IP CEF

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Step 1: Configure CEF 1. Configure CEF: –Start CEF switching to create the FIB table –Enable CEF switching on all core interfaces 2. Configure MPLS on a frame mode interface 3.(Optional) Configure the MTU size in label switching

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v ip cef [distributed] Router(config)# Step 1: Configure CEF (Cont.) Starts CEF switching and creates the FIB table The distributed keyword configures distributed CEF (running on VIP or line cards) All CEF-capable interfaces run CEF switching ip route-cache cef Router(config-if)# Enables CEF switching on an interface Usually not needed

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Monitoring IP CEF Displays a summary of the FIB show ip cef detail Router# Router#show ip cef detail IP CEF with switching (Table Version 6), flags=0x0 6 routes, 0 reresolve, 0 unresolved (0 old, 0 new) 9 leaves, 11 nodes, bytes, 9 inserts, 0 invalidations 0 load sharing elements, 0 bytes, 0 references 2 CEF resets, 0 revisions of existing leaves refcounts: 543 leaf, 544 node Adjacency Table has 4 adjacencies /32, version 0, receive /32, version 3, cached adjacency to Serial0/ packets, 0 bytes tag information set local tag: 28 fast tag rewrite with Se0/0.10, point2point, tags imposed: {28} via , Serial0/0.10, 0 dependencies next hop , Serial0/0.10 valid cached adjacency tag rewrite with Se0/0.10, point2point, tags imposed: {28}

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Configuring MPLS on a Frame Mode Interface

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Step 2: Configure MPLS on a Frame Mode Interface 1. Configure CEF 2. Configure MPLS on a frame mode interface: –Enable label switching on a frame mode interface –Start LDP or TDP label distribution protocol 3.(Optional) Configure the MTU size in label switching

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Step 2: Configure MPLS on a Frame Mode Interface (Cont.) Enables label switching on a frame mode interface Starts LDP on the interface mpls ip Router(config-if)# mpls label protocol [tdp | ldp | both] Router(config-if)# Starts selected label distribution protocol on the specified interface

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Configuring MPLS on a Frame Mode Interface: Example 1

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Configuring MPLS on a Frame Mode Interface: Example 2

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Configuring the MTU Size in Label Switching

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Step 3: Configure the MTU Size in Label Switching 1. Configure CEF 2. Configure MPLS on a frame mode interface 3.(Optional) Configure the MTU size in label switching: –Increase MTU on LAN interfaces

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Step 3: Configure the MTU Size in Label Switching (Cont.) Label switching increases the maximum MTU requirements on an interface, because of additional label header Interface MTU is automatically increased on WAN interfaces; IP MTU is automatically decreased on LAN interfaces Label-switching MTU can be increased on LAN interfaces (resulting in jumbo frames) to prevent IP fragmentation mpls mtu bytes Router(config-if)#

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Configuring Label Switching MTU: Example

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Summary MPLS configuration tasks include configuring IP CEF, tag switching, and setting MTU size. CEF is configured globally. Use the mpls ip command to enable MPLS on an interface level. To set MTU for labeled packets, use the mpls mtu interface configuration command.

© 2006 Cisco Systems, Inc. All rights reserved.ISCW v