CCNP TSHOOT Learning Guide/Chapter 7

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Troubleshooting Addressing Solutions

Package wordprocessing.png Under Construction

High Router CPU Load

TCP Timers

Campus1#<input>show tcp statistics</input>
<notice>Rcvd: 1660766 Total, 389 no port</notice>
      35 checksum error, 0 bad offset, 0 too short
      745428 packets (14484748 bytes) in sequence
      1376 dup packets (106935 bytes)
      10 partially dup packets (14 bytes)
      4 out-of-order packets (385 bytes)
      0 packets (0 bytes) with data after window
      7 packets after close
      0 window probe packets, 4 window update packets
      156 dup ack packets, 0 ack packets with unsend data
      694031 ack packets (17499170 bytes)
<notice>Sent: 1654082 Total, 4 urgent packets</notice>
      236042 control packets (including 20049 retransmitted)
      695206 data packets (17505653 bytes)
      285 data packets (29786 bytes) retransmitted
      1 data packets (1 bytes) fastretransmitted
      693531 ack only packets (673691 delayed)
      0 window probe packets, 3 window update packets
<notice>2403 Connections initiated, 34096 connections accepted, 4630 connections established
36518 Connections closed (including 25214 dropped, 22 embryonic dropped)
20334 Total rxmt timeout, 0 connections dropped in rxmt timeout
0 Keepalive timeout, 2 keepalive probe, 0 Connections dropped in keepalive</notice>

Switching Path

Slå CEF til globalt

Router(config)#<input>ip cef</input>

Slå cef til på et interface

Router(config-if)#<input>ip route-cache cef</input>

Er CEF slået til på et interface:

Campus1#<input>show ip interface vlan 139</input>
Vlan139 is up, line protocol is up
  Internet address is
  Broadcast address is
  Address determined by non-volatile memory
  MTU is 1500 bytes
  Helper addresses are
  Directed broadcast forwarding is enabled
  Multicast reserved groups joined:
  Outgoing access list is not set
  Inbound  access list is not set
  Proxy ARP is enabled
  Local Proxy ARP is disabled
  Security level is default
  Split horizon is enabled
  ICMP redirects are always sent
  ICMP unreachables are always sent
  ICMP mask replies are never sent
  IP fast switching is enabled
  <notice>IP CEF switching is enabled</notice>
  IP CEF switching turbo vector
  IP Null turbo vector
  IP multicast fast switching is enabled
  IP multicast distributed fast switching is disabled
  IP route-cache flags are Fast, CEF
  Router Discovery is disabled
  IP output packet accounting is disabled
  IP access violation accounting is disabled
  TCP/IP header compression is disabled
  RTP/IP header compression is disabled
  Probe proxy name replies are disabled
  Policy routing is disabled
  Network address translation is disabled
  BGP Policy Mapping is disabled
  Input features: MCI Check
  Output features: Check hwidb
  WCCP Redirect outbound is disabled
  WCCP Redirect inbound is disabled
  WCCP Redirect exclude is disabled

Troubleshooting CEF

Campus1#<input>show ip cef</input>
Prefix               Next Hop             Interface            Vlan4            drop           receive           Vlan4        attached             Vlan10        receive              Vlan10        attached             Vlan10      receive              Vlan10      attached             Vlan10      receive              Vlan10        attached             Vlan11        receive              Vlan11        attached             Vlan11        receive              Vlan11      receive              Vlan11          Vlan4          drop          Vlan4      attached             Vlan4      attached             Vlan4      attached             Vlan4      attached             Vlan4      attached             Vlan4      attached             Vlan4      receive              Vlan4        Vlan139          Vlan4       Vlan139     attached             Vlan139     receive              Vlan139     receive              Vlan139     attached             Vlan139    attached             Vlan139       Vlan139       Vlan139          multicast         receive          drop   receive