Networking

Hubs, Repeaters, Bridges, Switches, Routers and Gateways

Posted in Networking on May 14th, 2009 by Kedar – Be the first to comment

I have always wanted to do this. What better way to do this than when I am studying Computer Networks. Knowledge courtesy: Computer Networks by Tanenbaum.

Application Layer : Application Gateway
Transport Layer : Transport Gateway
Network Layer : Router
Data Link Layer : Bridge, Switch
Physical Layer : Repeater, Hub

Repeaters: Just amplify volts.
Hubs: Can connect many entities. Frames arriving from any one is sent out on all others.
Bridges: Bridges are used to connect LANs. They connect 2 ethernets. They do not examine packets. So they can transport any type of payloads – IPv4, IPv6, AppleTalk, ATM, OSI or any other kind. A bridge can have line cards for different network types and different speeds.
Switches: Switches also route on frame addresses. Swich is almost like a multi-port Bridge. However switches often are used to connect individual computers. Switches do not broadcast like hubs.
Routers: Examine addresses in packets and route based on them.

Fix DSL Stall

Posted in Networking on May 14th, 2009 by admin – Be the first to comment

These instructions are for PPPoE software users only. If you have DHCP or PPPoE through a router this can make things much worse. If your computer has to logon to access the internet ands you notice delays/freezes/stalls while the OS boots up or when browsing or at seemingly random times. The following will likely cure it:

  1. Open Control Panel.
  2. Open Network.
  3. Look for the first entry in the scroll box marked TCP/IP, that is associated with a hardware ethernet card (ignore dialup, especially Enternet or NTS and VPN type bindings). Note: If you have a 4060 USB modem, select TCP/IP-> Efficient Networks SpeedStream 4060 CIP/1483
  4. Select it and press properties
  5. Select IP address from the tab
    Is Obtain IP address automatically checked? If so, change that to Specify an IP address and enter 192.168.1.10, and 255.255.255.0, into IP address and subnet mask fields respectively.

  6. Click OK and OK, and the computer will build a driver information database and will require a reboot for the changes to take effect.

This assignment of a harmless local IP address to the TCP/IP settings bound (connected) to your network adapter, will stop the in-built DHCP services from waking up every 10 minutes to look for a DHCP server so that it can “fill in the blanks”.