RSSAll Entries in the "LAN General" Category

How to trace physical interface with MAC/IP address in Cisco Devices

In this post I will explain the steps to find the client/end user computer connected physical interface in large Network environment with multiple Access Switches connecting to the core switches or routers. This will help you to trace and troubleshoot devices like a PC or a laptop or other end devices. This is not a difficult task but can certainly be time consuming. You can trace the physical interface by using MAC address or IP address. You can find the MAC address with “sh ip arp” command of particular IP address in gateway router. Let’s start with an IP address. Find out gateway router while checking traceroute to the IP address then login into second hop IP address from end and enter “sh ip arp X.X.X.X” command. C:\>tracert Tracing route to over a maximum of 30 hops 1     1 ms     1 ms     2 ms 2     1 ms    <1 ms    <1 […]

What is the Difference Between Switch and Bridge in Networking

 Switch Vs Bridge S.No SWITCH BRIDGE 1  Switches are available in both manageable and non manageable.  Bridges are available only in non manageable 2 Number of ports are more than bridge Number of ports are less than switch 3 They can have separate spanning tree for  each VLANs in the switch They can have only one spanning tree instance per bridge. 4 Large frame buffers Low frame buffer 5 Switches are Hardware based, perform forwarding in hardware Bridges are software based, perform forwarding in software 6 Switches were just the next step which eliminated the collision domain completely Bridges were historically used to reduce the size of collision domain created by hubs 7 Supports cut-through switching Doesn’t supports cut-through switching 8  A switch is a network acces device that provides a centallized point for LAN communications,media connections and management activities-like Hub.  A bridge is an internetworking device used to contact separate […]

How to find Switch-Port with MAC- Address on a Cisco Catalyst Switch

Steps to find Switch-Port with MAC-address on Cisco Switch If you want to find a Switch port on a Cisco Switch with a specific IP address, you can fallow the below steps. It is very easy to find out using below commands with shortcut pipe command. Note these instructions are demonstrated on a Cisco IOS Software, Catalyst 4500 L3 Switch Running Software (cat4500-ENTSERVICESK9-M), Version 12.2(46)SG, RELEASE SOFTWARE (fc1). Lets start with an IP address on hand. If you have an IP address on hand quickly ping and check if the device is reachable. If device is reachable, then simply logon to one of your core Switches or Routers and issue a simple commad ” sh ip arp”. Cisco-Switch>sh ip arp Protocol  Address          Age (min)  Hardware Addr   Type   Interface Internet               2   0027.0d73.4980  ARPA   Vlan1 Internet            –      40f4.ecb1.ce40     ARPA   Vlan1 Internet             111    0000.0c07.ac01  ARPA   Vlan1 Internet           111    […]

Difference between Cut -through and Store-and-Forward Switching

When Layer 2 Ethernet switch initiates the forwarding decision, The Ethernet switch undergoes series of steps to determine whether to forward or drop a packet is what differentiates the cut-through Switch from store-and-forward Switch. Both store-and-forward and cut-through Layer 2 switches takes their forwarding decisions on the destination MAC address of data packets. They also learn MAC addresses as they examine the source MAC (SMAC) fields of packets as stations communicate with other nodes on the network. Cut-through Switches: In theory Cut-through switch receives and examines only the first 6 bytes of a frame, which carries the DMAC (Destination MAC ) address. However, practically cut-through switches wait until a few more bytes of the frame have been evaluated before they decide whether to forward or drop the packet. Enhanced Cut-through (Fragment Free) Switches: Enhanced cut-through switches checks the frame up to 64 bytes and looking for any errors. if not […]