Idea of Spanning Tree Protocol..!!!

Dear Valued Reader,

Today we are discuss important protocol of STP. We are think, this protocol is very important our networking sector. So, develop our knowledge……………

Spanning Tree Protocol

Spanning trees accomplish the goal of allowing physical redundancy, but with only one currently active path through a bridged network. Spanning tree uses the following features to accomplish the goal:

A)     All bridge interfaces eventually stabilize at either forwarding or blocking state. The forwarding interfaces are considered a part of the spanning tree.

B)      One of the bridges is elected as root. The election process includes all bridges claiming to be the root, until one bridge is considered best by all. All root bridge interfaces are in forwarding state.

C)      Each bridge receives hello BPDUs from the root, either directly or forwarded by another bridge. Each bridge can receive more than one such message on its interfaces. The port on which the least-cost BPDU is received is called the bridge’s root port. That port is placed in forwarding state.

D)     For each LAN segment, one bridge sends the forwarded BPDU with the lowest cost. That bridge is the designated bridge for that segment. That bridge’s interface on that segment is placed in forwarding state.

E)      All other interfaces are placed in blocking state.

F)      The root sends BPDUs every hellow time seconds. The other bridges expect to receive copies of these BPDUs so that they know that nothing has changed. The hellow time is defined in the BPDU itself, so all bridges use the same value.

G)     If a bridge does not receive a BPDU for Max Age seconds, it begins the process of causing the spanning tree to change. The reaction can vary from topology.(Max Age is defined in the BPDU itself,so all bridges use the same value.)

H)     One or more bridges decide to change interfaces from blocking to forwarding, or vice versa, depending on the change in the network. when moving from blocking to forwarding, the interim listening state is entered first. After the Forward Delay amount of time (another timer defined in the root BPDU), the state is changed to learning. After another Forward Delay amount of time, the interfaces is placed in forwarding state.

I)        When a switch first transitions to a listening state, the switch sends a TCN BPDU over the new path to the root, forcing switches to quickly remove invalid entries from their MAC address tables.

J)       The Spanning Tree Protocol includes these delays to help ensure that no temporary loops occur.

VLAN Trunking Protocol (VTP) …!!!

Today we are discuss VTP protocol. This protocol is very cisco switch platform. So,  develop an idea……………

VLAN Trunking Protocol

Cisco switches use the proprietary VTP to exchange VLAN configuration information between switches.VTP defines a Layer 2 messaging protocol that allows the switches to exchange VLAN configuration information so that the VLAN configuration stays consistent throughout a network. For instance, if you want to use VLAN 3 and name it “accounting,” you can configure that information in one switch, and VTP will distribute that information to the rest of the switches.VTP manages the additions, deletions, and name changes of VLANs across multiple switches, minimizing misconfigurations and configuration inconsistencies that can cause problems, such as duplicate VLAN names or incorrect VLAN-type settings.

VTP makes VLAN configuration easier. However, you have not yet seen how to configure VLANs, so to better appreciate VTP, consider this example: If a network has ten interconnected switches, and parts of VLAN 3 were on all ten switches, you would have to enter the same config command on all ten switches to create the VLAN. With VTP, you would create VLAN 3 on one switch, and the other nine switches would learn about VLAN 3 dynamically.

The VTP process begins with VLAN creation on a switch called a VTP server. The changes are distributed as a broadcast throughout the network. Both VTP clients and servers hear the VTP messages and update their configuration based on those messages. So VTP allows switched network solutions to scale to large sizes by reducing the manual configuration needs in the network.

Important Process of Password Recovery – Cisco Router …!!

Today we are discuss important process of password recovery for cisco router. This information is very important every network professional. So, develop your idea……………

The two keys to password recovery are knowing that ROMMON (Remote Monitor;a minimal Cisco IOS that allows router access incase the IOS is damaged or unavailable) enables you to reset the configuration register and that a console user can get into ROMMON mode by pressing the Break Key during the first 60  seconds after power-on.Knowing how to reset the configuration register enables you to boot the router (ignoring NVRAM),allowing the console user to see or change the system passwords.

Here are the basic steps associated with password recovery:

1.Turn the router off and then back on again.

2.Press the Break key within the first 60 seconds.

3. Change the configuration register so that bit 6 is 1 (CONFREG COMMAND).

4. Cause the router to load an IOS.(RELOAD command or just power off and on).

5. Avoid setup mode,which will be automatically prompted.

6. Enter privileged mode.

7. View startup configuration to see unencrypted passwords.(EX:SHOW STARTUP-CONFIG).

8. Use the appropriate commands to reset  any encrypted passwords (EX:ENABLE SECRET).

9. Change the configuration register back to the original value.

10. Save the new configuration to active changes (EX:COPY RUNNING-CONFIG STARTUP-CONFIG).

11. Reboot the router.