I’m about to setup two Cisco 3560-X at work and the plan is to interconnect with fibre. However when I was about to order C3KX-NM-1G I was told by my distributor that they can’t be delivered until November. Guess I
The facts of Ethernet – Round three
The previous post talked about autonegotiation. This time I will talk about cables and pinouts and how auto MDIX works. Although I’m not very old I still like to do it the old school way. I don’t rely on auto
The facts of Ethernet – Round two
Autonegotiation – Either you love it or you hate it but pretty much everyone has an opinion on it. I was going to write something more lengthy at first but decided a blog was the wrong place. Autonegotiation works by
Cisco ASA 5510 – Where did my gigabit ports go?!
I’m preparing some ASA 5510 firewalls at work which are going to replace two Cisco Pix firewalls. We ordered the ASA5510-SEC-BUN-K9 because we need failover and the gigabit ports. I unpacked the firewall and booted it up but when I
Authentication, authorization and accounting
Authentication, authorization and acounting is commonly called AAA. If you have more than a few network devices using local user accounts is not a scalable solution. The solution is to centralize the authentication either via a TACACS+ or a RADIUS
Quick facts about fibre standards
I don’t get to mess around with fibre a lot so I found the different standards and when to use what quite confusing. I’m doing a project right now where I need to connect two 3560 switches to a 3550.
The facts of Ethernet round one
Ethernet is the most used layer 2 protocol today and it’s dominance is not likely to end anytime soon. I decided to make a section with some quick facts about Ethernet. There is a lot to know about Ethernet but
The thrill of being a network engineer
Had a real busy day at work yesterday. When I came in to work in the morning I got alerted by the NOC that we had a major fault in one of our networks. The network is an open network
IP fragmentation
Every physical medium has a maximum size of packets it can send. This is called MTU (Maximum Transmission Unit). For Ethernet this is usually 1500 bytes. If we send packets that are larger than 1500 bytes fragmentation is needed. Fragmentation
ARP (Address Resolution Protocol)
ARP is one of the most used protocols and every netwoork engineer should have a good understanding of it. The purpose of ARP is to find out the hardware address for a host for which we know the IP. ARP