What is PVID in Cisco

PVID = Port Vlan ID
PVID (Port VLAN ID) is a default VLAN id assigned to frames coming to the port

Example 1.

interface fa0/1
  switchport mode access
  switchport access vlan 10
  switchport voice vlan 20
  switchport trunk native vlan 30

Here PVID is 10, as untagged frames will get into VLAN 10.

Example 2

interface fa0/2
  switchport mode trunk
  switchport access vlan 10
  switchport voice vlan 20
  switchport trunk native vlan 30

Here PVID is 30, as untagged frames will get into VLAN 30.

Cisco Verify md5 before upgrade

After load loaded the ios to router, remember to verify it, make sure md5 is match before reload –

# verify /md5 filesystem:filename md5-value

example –
router# verify /md5 disk1:c7200-js-mz 0f369ed9e98756f179d4f29d6e7755d3

output –
router# verify /md5 disk1:c7200-js-mz 0f369ed9e98756f179d4f29d6e7755d3
…………………………….
…………………………….
…………………………….
…………………………….
…………………………….
………………………….Done!
Verified (disk1:c7200-js-mz) = 0f369ed9e98756f179d4f29d6e7755d3

Cisco 1841 – Password Reset

Following is process to reset the password on Cisco C1841 Router,

Connect the console cable to Router C1841
Use the power switch in order to turn off the router, and then turn the router back on
Press Ctrl + Break on the terminal keyboard within 60 seconds of power up in order to put the router into ROMMON

Type confreg 0x2142 at the rommon 1> prompt in order to boot from Flash
*This step bypasses the startup configuration where the passwords are stored

Type reset at the rommon 2> prompt.
The router reboots, but ignores the saved configuration.

Type no after each setup question, or press Ctrl-C in order to skip the initial setup procedure.
Type enable at the Router> prompt.
You are in enable mode and should see the Router# prompt.
Type copy startup-config running-config in order to copy the nonvolatile RAM (NVRAM) into memory.

** Do not type copy running-config startup-config or write. These commands erase your startup configuration.

Type configure terminal
Type #enable secret in order to change the enable secret password.
Type config-register #config-register 0x2102
Type write memory or #copy running-config startup-config in order to commit the changes

** Remember to the steps of config-register 0x2102 , otherwise it will stay on 0x2142 previously where each time router boot, it won’t load the startup-config, and prompt for initialize the router.

Cisco Upgrade ROMMON

Some IOS releases require a ROMMON upgrade. Following is example for Cisco 1841 Router –

1. Go into the user privileged mode
2.type, upgrade rom-monitor file usbflash0:C1841_RM2.srec.124-13r.T5

The following message will appear:
This command will result in a ‘power-on reset’ of the router!
Continue? [yes/no]:

3. Type, yes and hit enter.

Show ver and you will see it is upgraded.