Re: Re: help, question about GRE

From: lzx (sglzx@163.com)
Date: Tue May 23 2006 - 06:32:06 ART


First thx for your reply .but i still don't understand that .
the link you give is talking much more about the tcp transmission .how about
the icmp packets and UDP packets,cause much of the application are based on
the udp ,such as file copy.

On the other hand ,a tunnel will pass through a lot of routers and switchs ,
Wether the 4th solution in the cisco link http://www.cisco.com/warp/public/105/56.html#solutions is practically ?

Another question is after i made these configuration:
  int tunnel 0
  ip mtu 1530 ---------configured by me
  tunnel source x.x.x.
  ....

i execute the two commands " show int tunnel 0 " and "show ip int tunnel 0" , but the
MTU displayed is different , which one is right?

c6509-r1-gdsz#sho int tunnel 0
Tunnel0 is up, line protocol is up
  Hardware is Tunnel
  Internet address is 10.10.10.2/30
  MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,
     reliability 255/255, txload 27/255, rxload 162/255
  Encapsulation TUNNEL, loopback not set
  Keepalive not set
  Tunnel source 61.242.2.114, destination 61.242.2.250
  Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
  Checksumming of packets disabled, fast tunneling enabled
  Last input 00:00:00, output 00:41:03, output hang never
  Last clearing of "show interface" counters 03:44:20
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 1
  Queueing strategy: fifo
  Output queue :0/0 (size/max)
  5 minute input rate 23000 bits/sec, 11 packets/sec
  5 minute output rate 10000 bits/sec, 7 packets/sec
     230657 packets input, 47348163 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     131055 packets output, 69863142 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
c6509-r1-gdsz#sho ip int tu
c6509-r1-gdsz#sho ip int tunnel 0
Tunnel0 is up, line protocol is up
  Internet address is 10.10.10.2/30
  Broadcast address is 255.255.255.255
  Address determined by setup command
  MTU is 1530 bytes
  Helper address is not set
  Directed broadcast forwarding is disabled
  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
  IP fast switching on the same interface is disabled
  IP Flow switching is disabled
  IP CEF switching is enabled
  IP Feature Fast switching turbo vector
  IP Feature CEF switching turbo vector
  IP multicast fast switching is enabled
  IP multicast distributed fast switching is disabled
  IP route-cache flags are Fast, Distributed, 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
  WCCP Redirect outbound is disabled
  WCCP Redirect inbound is disabled
  WCCP Redirect exclude is disabled
  BGP Policy Mapping is disabled
  IP multicast multilayer switching is disabled
c6509-r1-gdsz#
c6509-r1-gdsz#

        

======= 2006-05-23 08:53:00 DzTZ@4PEVPP45@#:=======

>Hi there,
>
>This does seem like a problem with you packet sizes. Send an extended
>ping sweep of sizes to make sure.
>
>Try dropping the mtu size of the interface to compensate for the
>overhead of the tunnel. The physical MTU of the interface will remain
>the same. Then run the ping sweep again and see how it goes.
>
>LH
>
>lzx wrote:
>> hi,
>> I have met a question about GRE tunnel. When i made a tunnel from 6509 to 76xx,
>> the users whose traffic route through this tunnel complaint that they almost could't
>> open every website on the internet, but they could ping these website's servers.
>> So i trust that is caused by the MTU of the tunnel. Then i changed the mtu of the
>> tunnel interface:
>> int tunnel 0
>> ip mtu 1530
>> ......
>>
>> after did that , i try again , but it still dosen't work. I doubt that if i should
>> change the physical interface of the tunnel using. Dose anyone have some succeed experience? thx a lot!
>>
>> My 6509 is the catos+ios (l2+l3) mix system.
>>
>> ios: Version 12.1(11b)E4
>>
>>
>> !!!!!!!!!!!!!!!!lzx
>> !!!!!!!!!!!!!!!!sglzx@163.com
>> !!!!!!!!!!!!!!!!!!!!2006-05-23
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>>
>>
>H

= = = = = = = = = = = = = = = = = = = =
                        

!!!!!!!!!!!!!!!!VB
@q#!
 
                                 
!!!!!!!!!!!!!!!!lzx
!!!!!!!!!!!!!!!!sglzx@163.com
!!!!!!!!!!!!!!!!!!!!2006-05-23



This archive was generated by hypermail 2.1.4 : Thu Jun 01 2006 - 06:33:22 ART