Cisco Tips

Sep 12 2009   7:34AM GMT

How to capture a text using PuTTY client?

Posted by: Yasir Irfan
PuTTY, Telnet, SSH, Telnet Client, Backup, running config, Startup config, Cisco Router, Cisco Switch, Cisco Tips, Cisco backup

 

PuTTY doesn’t need any introduction as its one of the widely used for remote console utility. PuTTY is an SSH and telnet client.

In day to day operational activities we do telnet or SSH to our Cisco routers or Switches, at times we need to backup a running or startup config or   a Cisco router or a switch or even some times we need to capture the terminal session logs for technical information etc.  This is can be easily done by using the PuTTY client.

I will show you how to capture a text using PuTTY client.

Once you have established a remote session with a Cisco router or a Switch, follow the following steps

 

Step 1: Right Click on the menu bar and select “Change Settings”

 

Step 2: Click logging under the icon Session.

 

Step 3: Then select “All Session Output”.

 

Step 4: Select the location using the browse button and enter the desired file name and click apply.

 

These steps will create the log file in the specified location and it will log everything you did in that particular telnet or SSH session.

Sep 8 2009   9:45AM GMT

Remote Telnet useful tips!

Posted by: Yasir Irfan
Switches, Cisco, Cisco Tips, Cisco 3560, Cisco Learning, Network Troubleshooting, IOS commands, Cisco Routers, reload, Cisco Switch, Cisco Troubleshooting, Router Troubleshooting, Telnet, SSH

 

We all work remotely with Cisco routers and Switches, we often do login to do some configuration changes in the Cisco routers and Switches. What if we configured wrongly in the live Cisco routers and Switches which are located in the remote sites, we don’t enjoy the liberty of resetting the devices unless we have control over the power distribution.

 

In this scenario the “reload” command proves to be very handy and useful. Just before making any changes to the configuration we can use the “reload” command as demonstrated below

 

ITKE-Cisco#reload in ?

Delay before reload (mmm or hhh:mm)

 

ITKE-Cisco#reload in 10

 

System configuration has been modified. Save? [yes/no]: no

Building configuration…

[OK]

Reload scheduled in 10 minutes by yasir on vty0 (10.0.0.5)

Proceed with reload? [confirm]

ITKE-Cisco#

ITKE-Cisco#

 

 

***

*** — SHUTDOWN in 0:05:00 —

***

 

The above demonstrated command will reload the device in 10 minutes. After applying the “reload” command we can proceed with the configuration changes. If things go wrong and we lost connectivity

to the device, then try back after 10 minutes as the device will get reloaded with the original startup-configuration which can helps us to restore the connectivity to the device.

 

Once we are sure about the new configuration and its working properly without any hassles there is always a way  “reload cancel” command is there to cancel the reload.

 

ITKE-Cisco#reload cancel

 

I find this command to be very handy and useful especially when we have to telnet or SSH to remote Cisco router or a Switch.

Jul 27 2009   5:55AM GMT

Reset Cisco 1250 Access Point to factory default settings

Posted by: Yasir Irfan
Cisco Aironet 1250, Access Point, Access Point troubleshooting, factory default settings, Cisco Access Point reset, write erase, Cisco Access Points, Cisco Tips, Cisco Commands, troubleshooting, Network Troubleshooting, web browser interface, Static IP, default settings, Cisco, Cisco Aironet 1250 Access Point, Wireless

 

If you want to reset the Cisco Aironet 1250 Access Point to factory default settings you have to use “Write erase or erase/all nvram” command, these commands resets the Cisco Aironet 1250 Access Point to factory default settings except the static IP Configured. This feature is really helpful if you reset the Cisco Aironet 1250 Access Point accidentally. Still you will have an option to access Cisco Aironet 1250 Access Point  using a web browser interface.

Mindful thinking from Cisco.

 

 

May 24 2009   11:35AM GMT

How to Determine the Serial Number of Supervisor Engine installed in a Cisco Catalyst 6500 Switch

Posted by: Yasir Irfan
Cisco Tips, Cisco Catalyst 6500 Switch, Cisco IOS Commands, Cisco Supervisor Engine, show idprom, Show commands

Imagine you have a Cisco Catalyst 6500 Switch, you were asked to figure out the Serial number for the Supervisor Engine Installed in your Cisco Catalyst 6500 Switch , it can done by using issuing the following command  “show idprom module” as shown in the below example.

 

ITKE-DAC-6500-BB01#show idprom module 7

IDPROM for module #7

  (FRU is ‘Supervisor Engine 720′)

  OEM String = ‘Cisco Systems’

  Product Number = ‘WS-SUP720-3B’

  Serial Number = ‘SAD084608JG’

  Manufacturing Assembly Number = ‘73-9740-01′

  Manufacturing Assembly Revision = ‘A0′

  Hardware Revision = 4.0

  Current supplied (+) or consumed (-) = -4.50A

ITKE-DAC-6500-BB01#

Mar 17 2009   12:28PM GMT

Don’t Panic for ICND 1 Simualtion questions.

Posted by: Yasir Irfan
ICND 1 Simualtion questions, ICND1, CCENT, Show ip interface, Show ip interface brief, CCNA, CCNA Exam, ICND1 Exam, CCENT Exam, Cisco Tips, Routing, IP Address, sho running-config

One of my colleagues went for the ICND 1 (640-822) exam and he failed to pass the exams with a small margin. He got few simulation questions, in which he was suppose the find out the IP address for the router interfaces connected in the topology provided. The show running command was disabled, he was suppose to use alternative IOS commands to determine the IP address assigned to the router interface.

 

In this scenario don’t panic,  the best command to determine the IP address assigned to interface s in any router is “show ip interface brief” or Show ip interfaces. Here is the sample output of these commands

 

ITKE-DAC-3745R01#sho ip interface brief

Interface                     IP-Address      OK? Method Status                Protocol

FastEthernet0/0         10.135.5.21     YES DHCP   up                    up     

FastEthernet0/1         192.168.1.2     YES NVRAM  up                    up     

Tunnel0                       172.31.31.50    YES NVRAM  up                    up     

ITKE-DAC-3745R01#

 

ITKE-DAC-3745R01#show ip interface

FastEthernet0/0 is up, line protocol is up

  Internet address is 10.135.5.21/24

  Broadcast address is 255.255.255.255

  Address determined by DHCP

  MTU is 1500 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 CEF Feature Fast switching 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

  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

FastEthernet0/1 is up, line protocol is up

  Internet address is 192.168.1.2/28

  Broadcast address is 255.255.255.255

  Address determined by non-volatile memory

  MTU is 1500 bytes

  Helper address is not set

  Directed broadcast forwarding is disabled

  Multicast reserved groups joined: 224.0.0.5 224.0.0.6

  Outgoing access list is not set

  Inbound  access list is 101

  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 enabled

  IP CEF switching is enabled

  IP CEF Flow Fast switching turbo vector

  IP multicast fast switching is enabled

  IP multicast distributed fast switching is disabled

  IP route-cache flags are Fast, Flow, CEF, Flow Cache

  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

  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

Tunnel0 is up, line protocol is up

  Internet address is 172.31.31.50/30

  Broadcast address is 255.255.255.255

  Address determined by non-volatile memory

  MTU is 1476 bytes

  Helper address is not set

  Directed broadcast forwarding is disabled

  Multicast reserved groups joined: 224.0.0.5

  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 enabled

  IP CEF switching is enabled

  IP CEF Flow Fast switching turbo vector

  IP multicast fast switching is enabled

  IP multicast distributed fast switching is disabled

  IP route-cache flags are Fast, Flow, CEF, Flow Cache

  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

  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

ITKE-DAC-3745R01#

Feb 18 2009   9:33AM GMT

Cisco Etherchannel Overview and how it can be configured in Cisco Catalyst Switches – Series 9

Posted by: Yasir Irfan
Cisco, Cisco Systems, Cisco Tips, Etherchannel, Etherchannel configuration, Etherchannel restrictions, Switches, Switching, Layer3 EtherChannel Configuration, PAGP EtherChannel Configuration, LACP, Cisco 3560 Catalyst Switch, Cisco online learning module, layer-2-design

Dear Friends

 Here we go,we are coming to the conclusion of the Ether channel series, I my self learned a lot and enjoyed while writing posts. Hope some of you are benifited from this series. Just before concluding this series,  I would stongly recommend you guys to check this wonderful quick learning module from Cisco Systems. which foucses on layer-2-design which might be helpful to you guys.

Feb 7 2009   5:52AM GMT

Cisco Etherchannel Overview and how it can be configured in Cisco Catalyst Switches – Series 8

Posted by: Yasir Irfan
Cisco, Cisco Systems, Cisco Tips, Etherchannel, Etherchannel configuration, Etherchannel restrictions, Switches, Switching, Layer3 EtherChannel Configuration, PAGP EtherChannel Configuration, LACP, Cisco 3560 Catalyst Switch

Now we are reaching towards the end of this series, one more post to go.  

Let’s proceed further and we will see how to configure a Layer 3 Etherchannel using the PAgp Protocol (Port Aggregation Protocol) in Cisco Catalyst Switches.

Here is the scenario which we will follow

 

From the above diagram we have two Cisco 3560 Catalyst Switches named ITKESW01 and ITKESW02.

We will configure a Layer 3 Etherchannel between the Cisco 3560 Catalyst Switches  ITKESW01 and ITKESW02. The  Giga Ethernet ports 0/45, 0/46/,0/47 & 0/48 on a Cisco 3560 Catalyst Switches  ITKESW01 are connected to Giga Ethernet ports 0/1,0/2,0/3 and 0/in Cisco 3560 Catalyst Switch  ITKESW02.

 

The configuration is as follows

 

Configuration in the Cisco 3560 Catalyst Switch  ITKESW01

 

ITKESW01#config t

ITKESW01(config)# interface port-channel 1

ITKESW01(config-if)# no switchport

ITKESW01(config-if)# no shutdown

ITKESW01(config-if)# ip address 192.168.1.1 255.255.255.0

ITKESW01(config-if)# end

 

ITKESW01#config t

ITKESW01(config)# interface range gigabitEthernet 0/45 – 48

ITKESW01(config-if-range)# no switchport

ITKESW01(config-if-range)# no ip address

ITKESW01(config-if-range)# channel-group 1 mode desirable

ITKESW01(config-if-range)#end

Note: This example shows how to configure Gigabit Ethernet ports 0/45 – 0/48   into port channel 1 with PAgP mode desirable

Note: The “no switchport” command is required to change interface from layer2 to layer3 mode.

 

Configuration in the Cisco 3560 Catalyst Switch  ITKESW02

ITKESW02#config t

ITKESW02(config)# interface port-channel 1

ITKESW02(config-if)# no switchport

ITKESW02(config-if)# no shutdown

ITKESW02(config-if)# ip address 192.168.1.2 255.255.255.0

ITKESW02(config-if)# end

 

ITKESW02#config t

ITKESW02(config)# interface range gigabitEthernet 0/1 – 4

ITKESW02(config-if-range)# no switchport

ITKESW02(config-if-range)# no ip address

ITKESW02(config-if-range)# channel-group 1 mode auto

ITKESW02(config-if-range)#end

Note: This example shows how to configure Gigabit Ethernet ports 0/1 – 0/4   into port channel 1 with PAgP mode auto

 

Note: The “no switchport” command is required to change interface from layer2 to layer3 mode.

 

Do use  “show etherchannel” command to display port-channel information after configuration and remember to save the configuration.

Jan 19 2009   5:49AM GMT

Cisco Etherchannel Overview and how it can be configured in Cisco Catalyst Switches – Series 7

Posted by: Yasir Irfan
Cisco, Cisco Systems, Cisco Tips, Etherchannel, Etherchannel configuration, Etherchannel restrictions, Switches, Switching, Layer 2 EtherChannel Configuration, LACP EtherChannel Configuration, LACP, Cisco 3560 Catalyst Switch

Here we go, I will continue the series of Etherchannel overview, in my last post related to Etherchannel I showed how to configure a Layer 2 Etherchannel using the Cisco’s proprietary a PAGP (port aggregation protocol) Protocol in Cisco Catalyst Switches.

Now it’s the time to proceed further and we will see how to configure a Layer 2 Etherchannel using the LACP Protocol (Link Aggregation Protocol) in Cisco Catalyst Switches.

Here is the scenario which we will follow

From the above diagram we have two Cisco 3560 Catalyst Switches named ITKESW01 and ITKESW02.

We will configure a Layer 2 Etherchannel between the Cisco 3560 Catalyst Switches  ITKESW01 and ITKESW02. The  Giga Ethernet ports 0/45, 0/46/,0/47 & 0/48 on a Cisco 3560 Catalyst Switches  ITKESW01 are trunk ports  and they are connected to Giga Ethernet ports 0/1,0/2,0/3 and 0/4 (also trunk ports in desirable mode) in Cisco 3560 Catalyst Switch  ITKESW02.

 

The configuration is as follows

 

Configuration in the Cisco 3560 Catalyst Switch  ITKESW01

 

First run the command “Show interfaces trunk

 

ITKESW01#sho interfaces trunk

 

Port        Mode             Encapsulation  Status        Native vlan

Gi0/45      desirable                n-isl         trunking            1

Gi0/46      desirable                n-isl         trunking            1

Gi0/47      desirable                n-isl         trunking            1

Gi0/48      desirable                n-isl         trunking            1

 

Port        Vlans allowed on trunk

Gi0/45        1-4094

Gi0/46        1-4094

Gi0/47        1-4094

Gi0/48        1-4094

 

Port        Vlans allowed and active in management domain

Gi0/45        1

Gi0/46        1

Gi0/47        1

Gi0/48        1

 

Port        Vlans in spanning tree forwarding state and not pruned

Gi0/45       1

Gi0/46       1

Gi0/47       1

Gi0/48       1

 

ITKESW01#

 

Second Step configure the Giga Ethernet ports 0/45 to 0/48 in the Etherchannel

 

ITKESW01#config t

ITKESW01(config)# interface range gigabitEthernet 0/45 – 48

ITKESW01(config-if-range)# channel-protocol lacp

 

Note: LACP protocol is configured to be used in this channel

 

ITKESW01 (config-if-range)# channel-group 1 mode active

Note: A logical port-channel interface is automatically created when ports are grouped into a channel group.

Configure the mode active to be used in LACP

Configuration in the Cisco 3560 Catalyst Switch  ITKESW02

 

ITKESW02#sho interfaces trunk

 

Port        Mode             Encapsulation  Status        Native vlan

Gi0/1      desirable            n-isl         trunking            1

Gi0/2      desirable            n-isl         trunking            1

Gi0/3      desirable            n-isl         trunking            1

Gi0/4      desirable            n-isl         trunking            1

 

 

Port        Vlans allowed on trunk

Gi0/1        1-4094

Gi0/2        1-4094

Gi0/3        1-4094

Gi0/4        1-4094

 

 

Port        Vlans allowed and active in management domain

Gi0/1        1

Gi0/2        1

Gi0/3        1

Gi0/4        1

 

 

Port        Vlans in spanning tree forwarding state and not pruned

Gi0/1       1

Gi0/2       1

Gi0/3       1

Gi0/4       1

 

ITKESW02#

 

Second Step configure the Giga Ethernet ports 0/1 to 0/4 in the Etherchannel

 

ITKESW02#config t

ITKESW02(config)# interface range gigabitEthernet 0/1 – 4

ITKESW02(config-if-range)#channel-protocol lacp

 

Note: LACP protocol is configured to be used in this channel

 

ITKESW02 (config-if-range)# channel-group 1 mode active

Note: A logical port-channel interface is automatically created when ports are grouped into a channel group.

Configure the mode active to be used in LACP

Now run show command to display the Etherchannel configurations on the Cisco 3560 Catalyst Switches  ITKESW01 and ITKESW02

ITKESW01#sho etherchannel 1 summary

Flags:  D - down        P - in port-channel

        I - stand-alone s - suspended

        H - Hot-standby (LACP only)

        R - Layer3      S - Layer2

        u - unsuitable for bundling

        U - in use      f - failed to allocate aggregator

        d - default port

 

Number of channel-groups in use: 1

Number of aggregators:           1

 

Group  Port-channel  Protocol    Ports

——+————-+———–+———————————————–

1      Po1(SD)          LACP      Gi0/45 (P)   Gi0/46 (P)  Gi0/47 (P)  Gi0/48 (P)  

ITKESW01#

 

ITKESW02#sho etherchannel 1 summary

Flags:  D - down        P - in port-channel

        I - stand-alone s - suspended

        H - Hot-standby (LACP only)

        R - Layer3      S - Layer2

        u - unsuitable for bundling

        U - in use      f - failed to allocate aggregator

        d - default port

 

Number of channel-groups in use: 1

Number of aggregators:           1

 

Group  Port-channel  Protocol    Ports

——+————-+———–+———————————————–

1      Po1(SD)          LACP     Gi0/1 (P)   Gi0/2 (P)  Gi0/3 (P)  Gi0/4 (P)  

ITKESW02#

 

Jan 6 2009   6:11AM GMT

Cisco Etherchannel Overview and how it can be configured in Cisco Catalyst Switches – Series 6

Posted by: Yasir Irfan
Cisco, Cisco Systems, Cisco Tips, Etherchannel, Etherchannel configuration, Etherchannel restrictions, Switches, Switching, Layer 2 EtherChannel Configuration, PAGP EtherChannel Configuration, LACP, Cisco 3560 Catalyst Switch

In the previous five posts I was talking about the Etherchannel  , types of protocols used , rules and restrictions applied to an Etherchannel  . Now it’s the time to see how an Etherchannel   can be configured in a Cisco Catalyst Switch.

An Etherchannel in a Cisco IOS can be defined as Layer 2 Etherchannel or a Layer 3 Etherchannel.

For a Layer 2 Etherchannel, physical ports are placed into an Etherchannel group.

For a Layer 3 Etherchannel, layer 3 SVI (Switch Virtual Interface) is created, and then the physical ports are placed into an Etherchannel group which is bound to the L3 SVI.

 

Now let’s see how to configure a Configure a Layer 2 Etherchannel in a Cisco Catalyst Switch using a PAGP (port aggregation protocol) Protocol. In my previous posts I did discussed about the PAGP protocol, it’s a Cisco proprietary protocol, can be applied only in Cisco Catalyst Switches.

Here is the scenario which we will follow

From the above diagram we have two Cisco 3560 Catalyst Switches named ITKESW01 and ITKESW02.

We will configure a Layer 2 Etherchannel between the Cisco 3560 Catalyst Switches  ITKESW01 and ITKESW02. The  Giga Ethernet ports 0/45, 0/46/,0/47 & 0/48 on a Cisco 3560 Catalyst Switches  ITKESW01 are trunk ports  and they are connected to Giga Ethernet ports 0/1,0/2,0/3 and 0/4 (also trunk ports) in Cisco 3560 Catalyst Switch  ITKESW02.

 

The configuration is as follows

 

Configuration in the Cisco 3560 Catalyst Switch  ITKESW01

 

First run the command “Show interfaces trunk

 

ITKESW01#sho interfaces trunk

 

Port        Mode             Encapsulation  Status        Native vlan

Gi0/45      on                        802.1q         trunking            1

Gi0/46      on                        802.1q         trunking            1

Gi0/47      on                        802.1q         trunking            1

Gi0/48      on                        802.1q         trunking            1

 

Port        Vlans allowed on trunk

Gi0/45        1-4094

Gi0/46        1-4094

Gi0/47        1-4094

Gi0/48        1-4094

 

Port        Vlans allowed and active in management domain

Gi0/45        1

Gi0/46        1

Gi0/47        1

Gi0/48        1

 

Port        Vlans in spanning tree forwarding state and not pruned

Gi0/45       1

Gi0/46       1

Gi0/47       1

Gi0/48       1

 

ITKESW01#

 

Second Step configure the Giga Ethernet ports 0/45 to 0/48 in the Etherchannel

 

ITKESW01#config t

ITKESW01(config)# interface range gigabitEthernet 0/45 – 48

ITKESW01(config-if-range)#channel-protocol pagp

 

Note: PAgP protocol is configured to be used in this channel

 

ITKESW01 (config-if-range)# channel-group 1 mode desirable

Note: A logical port-channel interface is automatically created when ports are grouped into a channel group.

Configure the mode desirable to be used in PAgP 

 

Configuration in the Cisco 3560 Catalyst Switch  ITKESW02

 

 

ITKESW02#sho interfaces trunk

 

Port        Mode             Encapsulation  Status        Native vlan

Gi0/1      on                        802.1q         trunking            1

Gi0/2      on                        802.1q         trunking            1

Gi0/3      on                        802.1q         trunking            1

Gi0/4      on                        802.1q         trunking            1

 

 

Port        Vlans allowed on trunk

Gi0/1        1-4094

Gi0/2        1-4094

Gi0/3        1-4094

Gi0/4        1-4094

 

 

Port        Vlans allowed and active in management domain

Gi0/1        1

Gi0/2        1

Gi0/3        1

Gi0/4        1

 

 

Port        Vlans in spanning tree forwarding state and not pruned

Gi0/1       1

Gi0/2       1

Gi0/3       1

Gi0/4       1

 

ITKESW02#

 

Second Step configure the Giga Ethernet ports 0/1 to 0/4 in the Etherchannel

 

ITKESW02#config t

ITKESW02(config)# interface range gigabitEthernet 0/1 – 4

ITKESW02(config-if-range)#channel-protocol pagp

 

Note: PAgP protocol is configured to be used in this channel

 

ITKESW02 (config-if-range)# channel-group 1 mode auto

Note: A logical port-channel interface is automatically created when ports are grouped into a channel group.

Configure the mode auto to be used in PAgP 

Now run show command to display the Etherchannel configurations on the Cisco 3560 Catalyst Switches  ITKESW01 and ITKESW02

ITKESW01#sho etherchannel 1 summary

Flags:  D - down        P - in port-channel

        I - stand-alone s - suspended

        H - Hot-standby (LACP only)

        R - Layer3      S - Layer2

        u - unsuitable for bundling

        U - in use      f - failed to allocate aggregator

        d - default port

 

Number of channel-groups in use: 1

Number of aggregators:           1

 

Group  Port-channel  Protocol    Ports

——+————-+———–+———————————————–

1      Po1(SD)          PAgP      Gi0/45 (P)   Gi0/46 (P)  Gi0/47 (P)  Gi0/48 (P)  

ITKESW01#

 

ITKESW02#sho etherchannel 1 summary

Flags:  D - down        P - in port-channel

        I - stand-alone s - suspended

        H - Hot-standby (LACP only)

        R - Layer3      S - Layer2

        u - unsuitable for bundling

        U - in use      f - failed to allocate aggregator

        d - default port

 

Number of channel-groups in use: 1

Number of aggregators:           1

 

Group  Port-channel  Protocol    Ports

——+————-+———–+———————————————–

1      Po1(SD)          PAgP      Gi0/1 (P)   Gi0/2 (P)  Gi0/3 (P)  Gi0/4 (P)  

ITKESW02#

 

In upcoming posts I will show how to configure a Layer 2 Etherchannel  using LACP protocol

Jan 3 2009   6:47AM GMT

Cisco Etherchannel Overview and how it can be configured in Cisco Catalyst Switches – Series 5

Posted by: Yasir Irfan
Cisco, Cisco Systems, Cisco Tips, Etherchannel, Etherchannel configuration, Etherchannel restrictions, Switches, Switching

Dear Friends,

 Hope it’s going to be a good beginning in the year 2009 and lest hope to see the peace and harmony all over the world.

Now let’s see what options are available for load balancing in an Etherchannel  bundle.  How does the Cisco Catalyst Switch determines which physical link in the Etherchannel  bundle to use to forward the data?

The answer is the Cisco Catalyst Switch uses a polymorphic algorithm taking key fields from the header of the packet to generate a hash to a physical link in the Etherchannel group.

Data sent across an Etherchannel is not load-balanced equally between all interfaces. Etherchannel  utilizes a load-balancing algorithm, which can be based on several forms of criteria, including: