State on Aaron's Worthless Words

BGP Notes - Neighbor States

Tue, 07 Jun 2011 00:00:00 +0000

Corrections appreciated.

Idle : There is no relationship, but the router sends out a TCP SYN to the neighbor to get the ball rolling.

Idle (admin) : The neighbor is admined down.

Connect : The router is waiting for the TCP connection to finish. If the TCP connection finishes, the router sends an open and transitions to OpenSent. If it times out, it transitions to Active.

Active : The router tries Cialis to initiate a TCP connection. If the TCP connection finishes, the router sends an open and transitions to OpenSent.

Stubby Post - Changing the Prompt on the ASA

Thu, 20 Jan 2011 00:00:00 +0000

RichardF commented on an article I wrote last November and mentioned the prompt command in the ASA. I never set aside any time to research it, but I finally took the time today while waiting for a maintenance window.

This is one of those little things in life that make me happy. Since the active ASA always has the same hostname and IP address, I find it hard to keep track of to which firewall I’m actually connected. That “configurtions are no long in sync” message you get when you conf t on the standby firewall really irks me. With the prompt command, I can see which firewall I’m on and in what state it is.

BCMSN Notes -- STP States

Fri, 22 May 2009 00:00:00 +0000

I’ve decided to take on the CCNP certification, so I’m going to wind up with a few posts will be more my own notes than anything. :)

A switch port on a 2960 comes up with a default configuration on VLAN 1. What happens from the perspective of spanning-tree?

First, the port comes up on blocking mode. This is to make sure that loops aren’t created without first listening to the network to see what’s going on.
Next, if the port may be a root or designated port, the port is moved to the listening state. In this state, the port can send and receives BPDUs only. It can’t send traffic, but it can discover the other switches participating in STP.
After the forwarding delay, the port goes into the learning state. In this state, the port can send and receive BPDUs as in listening, but it can now receive traffic. It can’t yet send any.
After the forwarding delay again, the port goes into the forwarding state. The port can now send and receive data.

If the port is configured with spanning-tree portfast, the mode goes from blocking directly to forwarding without going through these steps. Obviously you don’t want a switch plugged into a port configured for portfast since you may wind up with a loop.