What is Traceroute

Traceroute:-

Traceroute is a computer network diagnostics tool. It’s used for displaying the route and delays of packets in an IP network. Traceroute is a command-line interface tool and available in many operation system, like Windows, MACOS, Linux, FreeBSD. Traceroute also uses ICMP (Internet Control Message Protocol) message, but unlike ping it identifies every router in a path taken by the packets. Traceroute is useful for troubleshoot network because it can help identify where exactly the problem is. 

Traceroute Works:-

Traceroute sends a series of ICMP (Internet Control Message Protocol) echo request packets to destination. First series of message has a TTL (Time to Live) parameter set to 1, which means that the first router in a path will discard the packet and send an ICMP (Internet Control Message Protocol) Time Exceeded message. TTL (Time to Live) is then increased by one until the destination host is reached and an ICMP (Internet Control Message Protocol) echo reply message is received. Main host can then use received ICMP (Internet Control Message Protocol) message to identify all routers in a path. The TTL (Time to Live) vale also known as hop limit.

The traceroute command on windows is named Tracert. On UNIX like system and IOS traceroute it is invoked using the traceroute command.

Example of use “Tracert command” in windows

In this example you can see that the traceroute command has listed the IP address of the routers in the path.

What is Ping

Ping:-

Ping stands for Packet Internet Groper. Ping is perhaps the most commonly used tool to troubleshooting a network. Ping (Packet Internet Groper) is included with most operating systems, like available for UNIX and Unix-like operating systems, DOS, Microsoft Windows, and ReactOS. 

Mike Muuss written ping utility in December 1983 during employment at the Ballistic Research Laboratory, now the US Army Research Laboratory. Ping utility was created as a tool for troubleshooting problems in IP networks. Ping was first included in 4.3BSD. It is invoked using a ping command. Ping command uses ICMP (Internet Control Message Protocol) to reports errors and provides information related to IP packet processing. Ping works by sending an ICMP echo request message to the specified IP address. If the computer with the destination IP address is reachable, it responds with an ICMP echo reply message.

A ping command usually outputs some other information about a network performance, for example a round-trip time, a time to send an ICMP request packet and receive an ICMP reply packet.

VTP Modes

In the last article we were discuss about VTP (Vlan Trunking Protocol) and how VTP works. Now in this article i will tell you about VTP (Vlan Trunking Port) Modes. Each switch can us three different VTP Modes.

VTP Modes:-

1. VTP (Vlan Trunking Port) Server Mode

2. VTP (Vlan Trunking Port) Client Mode

3. VTP (Vlan Trunking Port) Transparent Mode

VTP Mode Explained:-

1. VTP Server Mode:-

 The VTP (Vlan Trunking port) Server Mode is the default mode for cisco switches. In this mode we can create or delete VLAN's on switches and the changes are advertised to the entire VTP doamin. In VTP Server Mode switch synchronizes VLAN configuration information with other switches and all VLAN's configurations are saved in NVRAM on the switch.

2. VTP Client Mode:- 

In VTP (Vlan Trunking Port) Client Mode switch can not change its VLAN configuration. It means we can not create or delete Vlan's on switches. In VTP Client Mode switch receive information from VTP servers and forwards VTP advertisements. The VLAN's configurations are not saved in NVRAM on the switch.