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How to configure Switching Method

ronnysaendig
Level 1
Level 1

Hi,

is it possible to set the switching method of a 2960G to Cut-throuh or Fragment free? Could somebody please post instructions on how to configure

and view the current switching mode which is used?

Thanks

R. Saendig

13 Replies 13

cadet alain
VIP Alumni
VIP Alumni

Hi,

is it possible to set the switching method of a 2960G to Cut-throuh or Fragment free?

As far as I know these are not supported on this platform. I think this is asics related.

Regards.

alain.

Don't forget to rate helpful posts.

What about a Cisco 3560G? Is it possible to use Cut-Through or any other Method instead of Store n Foreward?

My mean Problem is while switching a Multicasting Stream from 1 Device to another the Switch receives the Multicast on port gi0/1

but does not send it out on another Port. I´ve used Wireshark and figured out that the Flag for dont fragment is set to 1 within the IP Header.

Any suggestions on how to resolve this issue?

R. Saendig

Hi,

My mean Problem is while switching a Multicasting Stream from 1  Device to another the Switch receives the Multicast on port gi0/1

but  does not send it out on another Port. I´ve used Wireshark and figured  out that the Flag for dont fragment is set to 1 within the IP Header.

A switch when forwarding frames is operating at Layer 2 and so doesn't care about the IP header.

The DF bit signifies the upstream router  to not fragment the data if it should due to MTU being shorter on forward link than on receive link.

Is the port where the multicast stream is not forwarded in the same VLAN as others? if not then this is normal behaviour.

If not then maybe you've got CGMP or IGMP snooping on the switch.

Regards.

Alain.

Don't forget to rate helpful posts.

The Ports are in the same vlan. IGMP Snooping is disabled.

Still the same Problem. I have connected another unmanagement switch from a other vendor and the traffic is going through.

So this is a Cisco releated Problem? I have tried 2960G & 3560G Switches.

Thanks for helping me out.

Hi ,

Can you post the running config of the switch, the version of IOS and the CAM table in this VLAN.

Regards.

Alain.

Don't forget to rate helpful posts.

Switch#sh run

Building configuration...

Current configuration : 5143 bytes

!

version 12.2

no service pad

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname Switch

!

boot-start-marker

boot-end-marker

!

!

username test privilege 15 secret 5 $1$Av2L$nmoZUhRhq3tVL7UhRpFl11

!

!

no aaa new-model

system mtu routing 1500

!

!

!

!

crypto pki trustpoint TP-self-signed-1445192448

enrollment selfsigned

subject-name cn=IOS-Self-Signed-Certificate-1445192448

revocation-check none

rsakeypair TP-self-signed-1445192448

!

!

crypto pki certificate chain TP-self-signed-1445192448

certificate self-signed 01

  3082023F 308201A8 A0030201 02020101 300D0609 2A864886 F70D0101 04050030

  31312F30 2D060355 04031326 494F532D 53656C66 2D536967 6E65642D 43657274

  69666963 6174652D 31343435 31393234 3438301E 170D3933 30333031 30303032

  31335A17 0D323030 31303130 30303030 305A3031 312F302D 06035504 03132649

  4F532D53 656C662D 5369676E 65642D43 65727469 66696361 74652D31 34343531

  39323434 3830819F 300D0609 2A864886 F70D0101 01050003 818D0030 81890281

  8100BB6E 013A247E 5CA3E23F F00D1E80 7391175D A3DF7CBB 10AC0398 61D452BD

  0613F032 9506A5DC 1049546D 289D537C 57B9FE17 3F39E957 37AEF904 1B68BB5F

  766D059A 67D5937D A55FD1EC 739CFA5A B7E1C440 AAFB90DB D4FD678A 80B2C527

  5351B657 10F3E3A6 5DA8648B 1889FF33 EC02061B 0BB1DF80 5760706F 9DC5CE40

  F5970203 010001A3 67306530 0F060355 1D130101 FF040530 030101FF 30120603

  551D1104 0B300982 07537769 7463682E 301F0603 551D2304 18301680 14B2B35C

  F1A7A85B C534FB90 A619A369 6C84620C 7D301D06 03551D0E 04160414 B2B35CF1

  A7A85BC5 34FB90A6 19A3696C 84620C7D 300D0609 2A864886 F70D0101 04050003

  81810075 7D90BF00 DF95FC9E 7C444A23 E7B164E0 8FC00586 33B6D800 FF7FAB7D

  3C485D2B B38B0854 72269E94 172680C3 5758D28E 7CFD1F14 985CB1A2 F7E281F2

  AF5DBB17 AC5FFFB6 F20093A0 21440005 A44E2F2A B309FAE2 5D89CBC8 AE25361A

  D4DEC0B2 BF3B1C3D 735CCE05 44C4DD89 37C9C783 066B59FF E0318012 97B24E04 D3813E

  quit

!

!

!

spanning-tree mode pvst

spanning-tree extend system-id

!

vlan internal allocation policy ascending

!

!

!

interface GigabitEthernet0/1

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/2

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/3

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/4

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/5

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/6

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/7

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/8

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/9

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/10

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/11

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/12

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/13

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/14

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/15

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/16

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/17

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/18

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/19

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/20

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/21

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/22

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/23

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface GigabitEthernet0/24

spanning-tree portfast

spanning-tree bpdufilter enable

spanning-tree bpduguard enable

!

interface Vlan1

ip address 10.9.180.253 255.255.0.0

!

ip http server

ip http secure-server

ip sla enable reaction-alerts

!

line con 0

line vty 0 4

login

line vty 5 15

login

!

end

______________________________________________________________________________________________________________

Switch#sh ver

Cisco IOS Software, C2960 Software (C2960-LANBASEK9-M), Version 12.2(55)SE1, RELEASE SOFTWARE (fc1)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2010 by Cisco Systems, Inc.

Compiled Thu 02-Dec-10 08:16 by prod_rel_team

Image text-base: 0x00003000, data-base: 0x01800000

ROM: Bootstrap program is C2960 boot loader

BOOTLDR: C2960 Boot Loader (C2960-HBOOT-M) Version 12.2(44)SE5, RELEASE SOFTWARE (fc1)

Switch uptime is 21 hours, 9 minutes

System returned to ROM by power-on

System image file is "flash:c2960-lanbasek9-mz.122-55.SE1.bin"

This product contains cryptographic features and is subject to United

States and local country laws governing import, export, transfer and

use. Delivery of Cisco cryptographic products does not imply

third-party authority to import, export, distribute or use encryption.

Importers, exporters, distributors and users are responsible for

compliance with U.S. and local country laws. By using this product you

agree to comply with applicable laws and regulations. If you are unable

to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:

http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to

export@cisco.com.

cisco WS-C2960G-24TC-L (PowerPC405) processor (revision E0) with 65536K bytes of memory.

Processor board ID FOC1217W76E

Last reset from power-on

1 Virtual Ethernet interface

24 Gigabit Ethernet interfaces

The password-recovery mechanism is enabled.

64K bytes of flash-simulated non-volatile configuration memory.

Base ethernet MAC Address       : 00:21:56:23:E3:00

Motherboard assembly number     : 73-10015-06

Power supply part number        : 341-0098-02

Motherboard serial number       : FOC1217536B

Power supply serial number      : AZS121508Z2

Model revision number           : E0

Motherboard revision number     : A0

Model number                    : WS-C2960G-24TC-L

System serial number            : FOC1217W76E

Top Assembly Part Number        : 800-26673-03

Top Assembly Revision Number    : B0

Version ID                      : V03

CLEI Code Number                : COM3G00BRB

Hardware Board Revision Number  : 0x01

Switch Ports Model              SW Version            SW Image

------ ----- -----              ----------            ----------

*    1 24    WS-C2960G-24TC-L   12.2(55)SE1           C2960-LANBASEK9-M

Configuration register is 0xF

_________________________________________________________________________________________________________________

Switch#sh vlan

VLAN Name                             Status    Ports

---- -------------------------------- --------- -------------------------------

1    default                          active    Gi0/1, Gi0/2, Gi0/3, Gi0/4

                                                Gi0/5, Gi0/6, Gi0/7, Gi0/8

                                                Gi0/9, Gi0/10, Gi0/11, Gi0/12

                                                Gi0/13, Gi0/14, Gi0/15, Gi0/16

                                                Gi0/17, Gi0/18, Gi0/19, Gi0/20

                                                Gi0/21, Gi0/22, Gi0/23, Gi0/24

1002 fddi-default                     act/unsup

1003 token-ring-default               act/unsup

1004 fddinet-default                  act/unsup

1005 trnet-default                    act/unsup

VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  BrdgMode Trans1 Trans2

---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------

1    enet  100001     1500  -      -      -        -    -        0      0

1002 fddi  101002     1500  -      -      -        -    -        0      0

1003 tr    101003     1500  -      -      -        -    -        0      0

1004 fdnet 101004     1500  -      -      -        ieee -        0      0

1005 trnet 101005     1500  -      -      -        ibm  -        0      0

Remote SPAN VLANs

------------------------------------------------------------------------------

Primary Secondary Type              Ports

------- --------- ----------------- ------------------------------------------

Switch#sh mac address-table vlan 1
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
All    0100.0ccc.cccc    STATIC      CPU
All    0100.0ccc.cccd    STATIC      CPU
All    0180.c200.0000    STATIC      CPU
All    0180.c200.0001    STATIC      CPU
All    0180.c200.0002    STATIC      CPU
All    0180.c200.0003    STATIC      CPU
All    0180.c200.0004    STATIC      CPU
All    0180.c200.0005    STATIC      CPU
All    0180.c200.0006    STATIC      CPU
All    0180.c200.0007    STATIC      CPU
All    0180.c200.0008    STATIC      CPU
All    0180.c200.0009    STATIC      CPU
All    0180.c200.000a    STATIC      CPU
All    0180.c200.000b    STATIC      CPU
All    0180.c200.000c    STATIC      CPU
All    0180.c200.000d    STATIC      CPU
All    0180.c200.000e    STATIC      CPU
All    0180.c200.000f    STATIC      CPU
All    0180.c200.0010    STATIC      CPU
All    ffff.ffff.ffff    STATIC      CPU
   1    000e.0cc6.0ee8    DYNAMIC     Gi0/4
   1    001c.230f.d091    DYNAMIC     Gi0/2
   1    00a0.f911.0e8a    DYNAMIC     Gi0/4
Total Mac Addresses for this criterion: 23

Hi,

So the multicast stream enters g0/1 and is flooded everywhere except on which port?

Can you explain the topology, how are the multicast recipients linked to the network and same for source.

What did you do with wireshark?

Post output of sh int status and sh spannning-tree as well as sh int g0/1 and sh int XX where XX is interface not flooded.

Regards.

Alain.

Don't forget to rate helpful posts.

Switch#sh int stat
Vlan1
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor        655      98491          5        320
             Route cache          0          0          0          0
                   Total        655      98491          5        320
GigabitEthernet0/1
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0      14834    1576243
             Route cache          0          0          0          0
                   Total          0          0      14834    1576243
GigabitEthernet0/2
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0       4454     476554
             Route cache          0          0          0          0
                   Total          0          0       4454     476554
GigabitEthernet0/3
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/4
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0      15152    1594304
             Route cache          0          0          0          0
                   Total          0          0      15152    1594304
GigabitEthernet0/5
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/6
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/7
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/8
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/9
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/10
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/11
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/12
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/13
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/14
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/15
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/16
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/17
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/18
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/19
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/20
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/21
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/22
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/23
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/24
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0

Switch#sh spanning-tree

VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32769
             Address     0021.5623.e300
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     0021.5623.e300
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/1               Desg FWD 4         128.1    P2p Edge
Gi0/2               Desg FWD 4         128.2    P2p Edge
Gi0/4               Desg FWD 19        128.4    P2p Edge

attached to Gi0/2 and Gi0/3 are one workstation and one Laptop which i used to capture with wireshark.

The Stream enters Gi0/1 but does not get out of any Interface.

Thanks.

Hi,

It was sh interface status  I wanted.

attached to Gi0/2 and Gi0/3 are one workstation and one Laptop which i used to capture with wireshark.

The Stream enters Gi0/1 but does not get out of any Interface.

Where is Gi0/3 in the output of sh span ? what was the multicast destination? Was the workstation listening to that traffic?---> nestat -rn

In wireshark did you leave promiscuous mode- were you seeing BPDUs? and the laptop with wireshark was listening to this traffic?----> netstat -rn

Regards.

alain.

Don't forget to rate helpful posts.

Sorry my fault,

it´s not gi0/3 it was gi0/4....

Both were listen to...

Yes Wireshark is running in promiscuous Mode and Bpdu´s are been captured. Any Idea´s ?

Switch#sh int status

Port      Name               Status       Vlan       Duplex  Speed Type
Gi0/1                        connected    1          a-full a-1000 10/100/1000BaseTX
Gi0/2                        connected    1          a-full a-1000 10/100/1000BaseTX
Gi0/3                        notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/4                        connected    1          a-full  a-100 10/100/1000BaseTX
Gi0/5                        notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/6                        notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/7                        notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/8                        notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/9                        notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/10                       notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/11                       notconnect   1            auto   auto 10/100/1000BaseTX

Gi0/12                       notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/13                       notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/14                       notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/15                       notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/16                       notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/17                       notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/18                       notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/19                       notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/20                       notconnect   1            auto   auto 10/100/1000BaseTX
Gi0/21                       notconnect   1            auto   auto Not Present
Gi0/22                       notconnect   1            auto   auto Not Present
Gi0/23                       notconnect   1            auto   auto Not Present
Gi0/24                       notconnect   1            auto   auto Not Present

Hi,

I don't see anything in your config which could interfere with multicast flooding.

Can you ping this multicast address from a PC connected to Gi0/1 and  post wireshark capture file on gi0/4

Regards.

Alain.

Don't forget to rate helpful posts.

hi Alain,

thanks for your help so far. I will post it on Monday. I will use a local SPAN Configuration and post the output.

Thanks for helping me figuring out what the problem may cause.

Ronny

Hi Ronny,

I will use a local SPAN Configuration and post the output.

Use SPAN only for seeing Gi0/1 ingress traffic, to see the flooding on Gi0/4 just put a laptop with wireshark on it and capture in promiscuous.

Regards.

Alain.

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