One More Handy Switching Command - Quick way to check the Root SW

So here is another handy command to find Root SW status locally.

CoreSW#show spanning-tree | inc VLAN|This 

VLAN0001
VLAN0020
             This bridge is the root
VLAN0060
             This bridge is the root
VLAN0160
             This bridge is the root
VLAN0163
             This bridge is the root

The output shows that this SW is the root bridge for all configured VLANs except for vlan 1

Regards,

Deepak Arora

Troubleshooting Layer 1 Cabling Issues - Cisco Catalyst Switches TDR Feature

Cisco TDR (Time Domain Reflectometer)

In Cisco IOS Release 12.1(19)EA1 or later, you can use the Time Domain Reflector (TDR) feature to diagnose and resolve cabling problems. When running TDR, a local device sends a signal through a cable and compares the reflected signal to the initial signal.

TDR is supported only on 10/100/100 copper Ethernet ports. It is not supported on 10/100 ports, 10-Gigabit module ports, or on SFP module ports.

TDR can detect these cabling problems: 

•Open, broken, or cut twisted-pair wires—The wires are not connected to the wires from the remote device.

•Shorted twisted-pair wires—The wires are touching each other or the wires from the remote device. For example, a shorted twisted pair can occur if one wire of the twisted pair is soldered to the other wire.

If one of the twisted-pair wires is open, TDR can find the length at which the wire is open.

Use TDR to diagnose and resolve cabling problems in these situations:

•Replacing a switch

•Setting up a wiring closet

•Troubleshooting a connection between two devices when a link cannot be established or when it is not operating properly 

Example:

core-switch#test cable-diagnostics tdr interface gi0/24
TDR test started on interface Gi0/24
A TDR test can take a few seconds to run on an interface
Use 'show cable-diagnostics tdr' to read the TDR results.


core-switch#show cable-diagnostics tdr interface gigabitEthernet 0/24
TDR test last run on: November 19 14:54:18

Interface Speed Local pair Pair length        Remote pair Pair status
--------     -----   ----------- --------------       -------------- ---------------
Gi0/24    1000M  Pair A     4    +/- 4  meters Pair A        Normal             
                        Pair B     4    +/- 4  meters Pair B        Normal             
                        Pair C     5    +/- 4  meters Pair D        Normal             
                        Pair D     4    +/- 4  meters Pair C        Normal

It means Gi0/24 is running on 1000 Mbps speed, All four pairs have cable length of 4 meters & corresponding remote pair side (for local pair) is working Normally.

The previous command is set to be deprecated sometime in the future and will be replaced by:

" show diagnostic result interface GigabitEthernet 0/24 "


Thanks!

Deepak Arora

The New Cisco ISR G2 Series

http://www.cisco.com/assets/prod/rt/isr/whats-new-isrg2.html

Some more handy "show" commands for CCIE Lab students...hmmm... actually for everyone to know

So here are some quick tips from real world prospective which will definitely save up your time in production networks before you start scratching your head 
:)

1. Here is a quick tip about alias...we all know how to configure that, personally I don't use that at all but some guys prefer it....anyways keep in mind next time you just create an Alias is if you type an alias and type space after it before hitting Enter...it's not gonna work like other commands does...let me make it a bit more clear to understand...lets say for demo I am counting * as a space character and my alias is say DEEPAK for sh version


now if I type Router#DEEPAK* and hit enter...it will not work but if I type Router#DEEPAK and hit enter...it will work just fine...but this space after command does work for all normal commands and doesn't make difference in execution of it like Router#sh version* or Router#sh ver.....both will display same output and will actually work.


2. Few handy show commands for those who are aiming for CCIE R&S lab like me ...basically this helps you see what exactly you wanna see like I love 

"sh ip int br | i up"

"sh ip int br | e unassigned"

"sh ver | i IOS"

and one special switching command: switch#sh ver | i Base


and here is the killer command that I just figured out today after beating my head against the wall to figure out the correct syntax...actually took me quite a few minutes before figuring it out...but finally got it rightly :)

"sh ip int br | e unassigned|down"

Regards,

Deepak Arora

Difference between CBAC & ZBF

http://www.cisco.com/en/US/prod/collateral/vpndevc/ps5708/ps5710/ps1018/prod_white_paper0900aecd806f31f9.pdf

Nice Website To Practise Prefix-Lists

http://catspace.com/goodies/prefix.htm

Another Proposed Solution for Static Route Over FR issue

Hello Everyone,

Here is an another proposed solution by me for my previous Static Routes over FR issue post. I was just trying to grab someone GRE concepts so I thought to lab up that scenario again and try to fix it with GRE keepalives this time. Although you might see different ip addressing this time, but I have attached "sh ip int b" output to simplify that for you.

Just as a side note - GRE keepalives can be enabled on one side and it will work fine. It's not like serial or Ethernet keepalives which are to be enabled on both sides.

http://deepakarora1984.blogspot.com/2008/12/static-route-issue-over-frame-relay.html

R1
---
R1(config)#do term len 0
R1(config)#do sh run
Building configuration...

Current configuration : 1171 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
no ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface Loopback1
 ip address 100.100.100.1 255.255.255.0
!
interface Tunnel0
 ip address 150.0.0.1 255.0.0.0
 keepalive 1 3
 tunnel source Serial0/0
 tunnel destination 1.1.1.1
!
interface Serial0/0
 ip address 1.1.1.0 255.255.255.254
 encapsulation frame-relay
 serial restart-delay 0
!
interface Serial0/1
 ip address 2.2.2.0 255.255.255.254
 serial restart-delay 0
!
interface Serial0/2
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial0/3
 no ip address
 shutdown
 serial restart-delay 0
!
ip http server
ip forward-protocol nd
ip route 3.3.3.0 255.255.255.0 2.2.2.1
ip route 200.200.200.0 255.255.255.0 150.0.0.2
ip route 200.200.200.0 255.255.255.0 2.2.2.1 10
!
!
!
access-list 101 permit ip 150.0.0.0 0.255.255.255 200.0.0.0 0.255.255.255
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
!
!
end

R1(config)#
R1(config)#do sh ip int b
Interface                  IP-Address      OK? Method Status                Prot
ocol
Serial0/0                  1.1.1.0         YES manual up                    up

Serial0/1                  2.2.2.0         YES manual up                    up

Serial0/2                  unassigned      YES unset  administratively down down

Serial0/3                  unassigned      YES unset  administratively down down

Loopback0                  10.0.0.1        YES manual up                    up

Loopback1                  100.100.100.1   YES manual up                    up

Tunnel0                    150.0.0.1       YES manual up                    up

R1(config)#
R1(config)#do sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

S    200.200.200.0/24 [1/0] via 150.0.0.2
     1.0.0.0/31 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Serial0/0
     2.0.0.0/31 is subnetted, 1 subnets
C       2.2.2.0 is directly connected, Serial0/1
     100.0.0.0/24 is subnetted, 1 subnets
C       100.100.100.0 is directly connected, Loopback1
     3.0.0.0/24 is subnetted, 1 subnets
S       3.3.3.0 [1/0] via 2.2.2.1
     10.0.0.0/24 is subnetted, 1 subnets
C       10.0.0.0 is directly connected, Loopback0
C    150.0.0.0/8 is directly connected, Tunnel0
R1(config)#
---------------------------------------------------

R2
---
R2(config)#do term len 0
R2(config)#do sh run
Building configuration...

Current configuration : 1097 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R2
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
no ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface Loopback1
 ip address 200.200.200.1 255.255.255.0
!
interface Tunnel0
 ip address 150.0.0.2 255.0.0.0
 keepalive 1 3
 tunnel source Serial0/0
 tunnel destination 1.1.1.0
!
interface Serial0/0
 ip address 1.1.1.1 255.255.255.254
 encapsulation frame-relay
 serial restart-delay 0
!
interface Serial0/1
 ip address 3.3.3.1 255.255.255.254
 serial restart-delay 0
!
interface Serial0/2
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial0/3
 no ip address
 shutdown
 serial restart-delay 0
!
ip http server
ip forward-protocol nd
ip route 2.2.2.0 255.255.255.0 3.3.3.0
ip route 100.100.100.0 255.255.255.0 150.0.0.1
ip route 100.100.100.0 255.255.255.0 3.3.3.0 10
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
!
!
end

R2(config)#
R2(config)#do sh ip int brief
Interface                  IP-Address      OK? Method Status                Prot
ocol
Serial0/0                  1.1.1.1         YES manual up                    up

Serial0/1                  3.3.3.1         YES manual up                    up

Serial0/2                  unassigned      YES unset  administratively down down

Serial0/3                  unassigned      YES unset  administratively down down

Loopback0                  20.0.0.1        YES manual up                    up

Loopback1                  200.200.200.1   YES manual up                    up

Tunnel0                    150.0.0.2       YES manual up                    up

R2(config)#
R2(config)#do sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

C    200.200.200.0/24 is directly connected, Loopback1
     1.0.0.0/31 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Serial0/0
     2.0.0.0/24 is subnetted, 1 subnets
S       2.2.2.0 [1/0] via 3.3.3.0
     100.0.0.0/24 is subnetted, 1 subnets
S       100.100.100.0 [1/0] via 150.0.0.1
     3.0.0.0/31 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Serial0/1
     20.0.0.0/24 is subnetted, 1 subnets
C       20.0.0.0 is directly connected, Loopback0
C    150.0.0.0/8 is directly connected, Tunnel0
R2(config)#
-----------------------------------------------------------------

R3
---
R3#term len 0
R3#sh run
Building configuration...

Current configuration : 825 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R3
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
!
no ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface Serial0/0
 ip address 2.2.2.1 255.255.255.254
 no ip route-cache
 serial restart-delay 0
!
interface Serial0/1
 ip address 3.3.3.0 255.255.255.254
 no ip route-cache
 serial restart-delay 0
!
interface Serial0/2
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial0/3
 no ip address
 shutdown
 serial restart-delay 0
!
ip http server
ip forward-protocol nd
ip route 100.100.100.0 255.255.255.0 2.2.2.0
ip route 200.200.200.0 255.255.255.0 3.3.3.1
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
line con 0
line aux 0
line vty 0 4
!
!
end

R3#
R3#sh ip int brief
Interface                  IP-Address      OK? Method Status                Prot
ocol
Serial0/0                  2.2.2.1         YES manual up                    up

Serial0/1                  3.3.3.0         YES manual up                    up

Serial0/2                  unassigned      YES unset  administratively down down

Serial0/3                  unassigned      YES unset  administratively down down

R3#
R3#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

S    200.200.200.0/24 [1/0] via 3.3.3.1
     2.0.0.0/31 is subnetted, 1 subnets
C       2.2.2.0 is directly connected, Serial0/0
     100.0.0.0/24 is subnetted, 1 subnets
S       100.100.100.0 [1/0] via 2.2.2.0
     3.0.0.0/31 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Serial0/1
R3#