CEF

Packets that CEF cannot handle: 
- IP Header Options
- Expiring TTL 
- Tunnel int
- Exceed MTU 
- IGMP Redirect

Load Balancing Options 
- Per-Packets
- Per-Dessession (Session)


IOU1(config)#ip cef load-sharing algorithm universal

CLIENT#traceroute 8.8.8.8 probe 10
Type escape sequence to abort.
Tracing the route to 8.8.8.8
VRF info: (vrf in name/id, vrf out name/id)
  1 1.1.1.1 5 msec 4 msec 1 msec 5 msec 4 msec 9 msec 5 msec 0 msec 2 msec 1 msec
  2 10.12.0.2 9 msec 10 msec 9 msec 9 msec 9 msec 9 msec 9 msec 30 msec 9 msec 9 msec
  3 10.24.0.4 18 msec 17 msec 23 msec 14 msec 17 msec 18 msec 18 msec 17 msec 17 msec 13 msec
  4 10.48.0.8 27 msec 27 msec 26 msec 26 msec 25 msec 26 msec 25 msec 28 msec 26 msec 25 msec
  
IOU1(config)#do show ip cef 8.8.8.8 255.255.255.255 internal
8.8.8.8/32, epoch 0, RIB[I], refcount 5, per-destination sharing
  sources: RIB
  feature space:
   IPRM: 0x00028000
  ifnums:
   Serial2/0(11)
   Serial2/1(12)
  path B1F3A7D8, path list B309782C, share 1/1, type attached nexthop, for IPv4
  nexthop 10.12.0.2 Serial2/0, adjacency IP adj out of Serial2/0 B4F0C268
  path B1F3A848, path list B309782C, share 0/1, type attached nexthop, for IPv4
  nexthop 10.13.0.3 Serial2/1, adjacency IP adj out of Serial2/1 B4F0C138
  output chain:
    loadinfo B22C790C, per-session, 2 choices, flags 0083, 5 locks
    flags: Per-session, for-rx-IPv4, 2buckets
    2 hash buckets
      < 0 > IP adj out of Serial2/0 B4F0C268
      < 1 > IP adj out of Serial2/1 B4F0C138
    Subblocks:
     None


IOU1(config)#ip cef load-sharing algorithm include-ports destination

CLIENT#traceroute 8.8.8.8 probe 10
Type escape sequence to abort.
Tracing the route to 8.8.8.8
VRF info: (vrf in name/id, vrf out name/id)
  1 1.1.1.1 5 msec 5 msec 4 msec 5 msec 5 msec 5 msec 4 msec 4 msec 4 msec 6 msec
  2 10.13.0.3 6 msec
    10.12.0.2 9 msec 8 msec 9 msec 8 msec 8 msec
    10.13.0.3 9 msec
    10.12.0.2 8 msec 8 msec 11 msec
  3 10.36.0.6 17 msec
    10.24.0.4 17 msec 18 msec 17 msec 17 msec
    10.36.0.6 17 msec 14 msec
    10.24.0.4 18 msec 18 msec 17 msec
  4 10.48.0.8 27 msec 26 msec
    10.68.0.8 27 msec
    10.48.0.8 25 msec 26 msec 27 msec
    10.68.0.8 26 msec
    10.48.0.8 25 msec 26 msec 26 msec
 
IOU1#show rib client
Client name          Handle     WalkQ  WalkQ by Owner
IP Static Route        1          0      0
IP Static Default Ne   2          0      0
App Route              3          0      0

Cisco CCNP Switch Chapter 11

Multilayer Switching

#Layer 2 Port Configuration
Switch(config)#interface fa1/1
Switch(config-if)#switchport

#Layer 3 Port Configuration
Switch(config)#interface fa1/2
Switch(config-if)#no switchport
Switch(config-if)#ip address 192.168.1.254 255.255.255.0

#Verify Configuration
Switch#show interface fa1/1 switchport

#SVI Port Configuration

*On multilayer switch, you can enable L3 functionality for an entire VLAN on the switch. (This address will be GW)

#Define or identify the VLAN interface, then assign any L3 Address
Switch(config)#interface vlan 10 
Switch(config-if)#ip address 192.168.10.254 255.255.255.0

#Enable SEF
Switch(config)#ip sef

* Switched Virtual Interface (SVI)
* Cisco Express Forwarding (CEF)
* Forwarding Information Base (FIB)

#How Cisco Switches Use CEF

#Exceptions to CEF

* Packet with header options
* Packet with TTL expired
* Packets destined to a tunnel interface
* Packets with unsupported encapsulations

* Packets requiring fragmentation (MTU exceeded)

#Displaying FIB Table Entries for a Specified VLAN
Switch#show ip cef vlan 10

#Displaying FIB Table Entries for a Specified IP Prefix
Switch#show ip cef 10.1.0.0 255.255.0.0 longer-prefixes

#Displaying Detailed CEF entery Information
Switch#show ip cef 10.1.0.0 255.255.0.0 detail

#Displaying the Total Number of Known Adjacencies
Switch#show adjacency summary

#Displaying Detailed Information about Adjacencies
Switch#show adjacency vlan 10 detail

#Displaying Adjacencies in the CEF Glean state
Switch#show ip cef adjacency glean