Archive for the “Spanning-Tree” Category


Sorry, this entry is only available in Portugues.

Comments No Comments »

Hello Guys,

The staff of the forum blog.ccna.com.br / forum posted a link containing several summaries of excellent quality, calledcheatsheets, written by the staff of the site Life Packet which includes several topics that are scope of CCNA. Below, shows the direct links for each of these cheatsheets.

Access-Lists, EIGRP, IPv6, OSPF, spanning-tree, Subnetting, VLAN, Wireless 802.11

Link to the package

Image of the page with summaries:

Página com os resumos da Packet Life

Abrasive,

Maurício.

Comments No Comments »

The STP (spanning-Tree Protocol) runs on bridges and switches exchange information through the BPDUs (Bridge Protocol Data Units). These BPDUs contain configuration messages and include the ID of each bridge and are sent via broadcast frames.
For operation of an STP Root Bridge is elected (the root switch). This switch-root becomes the focus of the network, and the choices of the root port, port-designated and non-designated network and all updates are seen by the prospect of the root switch. To elect him the following parameters are used:

1st Lower priority value (default is 32768);
2nd Minor MAC Address (0000.aaaa.bbbb.cccc.dddd.eeee is less than 0000.aaa b. Bbbb.cccc.dddd.eeee).

The doors may have the following roles:

Role Description
Root port port on a switch that has lower cost to root bridge. Where are the forwarding state).
Designated port port on a switch to maintain connectivity. When there are redundant connections, the port with higher bandwidth is chosen. If the band widths are the same, the port with the lowest number will be chosen (eg e1 chosen instead of E8).
Non-designated port port that is in blocking state. When a designated port loses connectivity to this port is, until it receives back to update the state blocking

The figure below shows a topology with the terms discussed above:

Papéis das portas no Spanning-Tree.

Roles of the ports spanning-Tree.

Have seen the papers that have doors. Now, will see the states where they can find. Typically, the switches are blocking orforwarding state. Below is presented each of the states in the sequence in which they occur.

State Description
Blocking Do not forward frames. Receives and analyzes BPDUs. By connecting a switch, it is in blocking state.
Listening Do not forward frames, but receives and analyzes BPDUs to make sure that no loops occur on the network.
Learning Do not forward frames, and receives BPDUs analyzes and records the MAC addresses of devices connected directly.
Forwarding Sends and receives frames and everything. A port in this state is regarded as having the lowest cost to the root switch.

Below is presented the timers of BPDUs:

Timers de cada um tipo de BPDU do STP (Spanning-Tree Protocol).

Timers for each type of BPDU STP (spanning-Tree Protocol).

Below is a flash animation that presents very intuitive the process of learning the spanning-Tree. A MUST.

Below, follow the links to reference that were used to produce the summary.

An interesting, which deepens the matter is the third reference. Can be found translated (by Google) here.

A Abrasive,

Maurício.

References:

- Filippeti, M. - “CCNA 4.1 - Complete Study Guide, Visual Books/2008.

- Cisco NetAcademy, Academy Connection. “Cisco Study Material official.” <http://cisco.netacad.net>. Acesso em: 03/03/2008.

- Cisco Systems inc. “Understanding and Configuring spanning Tree Protocol (STP) on Catalyst Switches”.<Http://www.cisco.com/en/US/tech/tk389/tk621/technologies_configuration_example09186a008009467c.shtml>. Acesso em: 03/03/2008.

Comments No Comments »

Hello Guys,

I found this laboratory on the Internet, dedicated to learning how the convergence of the protocol STP (spanning-Tree Protocol).

With it you can see who is the Root Bridge, the Root, Designed and Non-designed ports and monitor the convergence of the network as links off the topology and Switchs.

Laboratorio spanning-Tree Protocol STP

Below a picture of the laboratory.

Topologia Laboratório Spanning Tree STP.

Spanning-tree topology of the lab.

A Abrasive staff.

Maurício.

Comments 2 Comments »