Hop (networking)
Encyclopedia
Data packets often have to go through routers (more generally: gateway
s), if not several, before they reach their final destination. Each time packets are passed to the next router a hop occurs. (To see how many hops it takes to get from one host to another ping
or traceroute
/tracepath commands can be used).
known as "time to live
", and "Hop Limit" in IPv6
, this field specifies a limit on the number of hops a packet is allowed before it should be discarded. This prevents packets from following a loop forever.
of a destination network and the IP address of the next gateway (next hop) along the path to the final network destination. Using a routing table to store a next hop for each 'known' destination is called next-hop forwarding. Therefore a given gateway only knows one step along the path, not the complete path to a destination. It is also key to know that the next hops listed in a routing table are on networks to which the gateway is directly connected to.
Gateway (telecommunications)
In telecommunications, the term gateway has the following meaning:*In a communications network, a network node equipped for interfacing with another network that uses different protocols....
s), if not several, before they reach their final destination. Each time packets are passed to the next router a hop occurs. (To see how many hops it takes to get from one host to another ping
Ping
Ping is a computer network administration utility used to test the reachability of a host on an Internet Protocol network and to measure the round-trip time for messages sent from the originating host to a destination computer...
or traceroute
Traceroute
traceroute is a computer network diagnostic tool for displaying the route and measuring transit delays of packets across an Internet Protocol network. Traceroute is available on most operating systems....
/tracepath commands can be used).
Hop Count
The distance between two hosts. The hop count n means that n gateways separate the source host from the destination host.Hop Limit
In IPv4IPv4
Internet Protocol version 4 is the fourth revision in the development of the Internet Protocol and the first version of the protocol to be widely deployed. Together with IPv6, it is at the core of standards-based internetworking methods of the Internet...
known as "time to live
Time to live
Time to live is a mechanism that limits the lifespan of data in a computer or network. TTL may be implemented as a counter or timestamp attached to or embedded in the data. Once the prescribed event count or timespan has elapsed, data is discarded. In computer networking, TTL prevents a data...
", and "Hop Limit" in IPv6
IPv6
Internet Protocol version 6 is a version of the Internet Protocol . It is designed to succeed the Internet Protocol version 4...
, this field specifies a limit on the number of hops a packet is allowed before it should be discarded. This prevents packets from following a loop forever.
Next Hop
Routing term used for the next gateway to which packets should be forwarded along the path to their final destination. One technique to make content of a routing table smaller is called next-hop routing.Next Hop Forwarding
A routing table usually contains the IP addressIP address
An Internet Protocol address is a numerical label assigned to each device participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing...
of a destination network and the IP address of the next gateway (next hop) along the path to the final network destination. Using a routing table to store a next hop for each 'known' destination is called next-hop forwarding. Therefore a given gateway only knows one step along the path, not the complete path to a destination. It is also key to know that the next hops listed in a routing table are on networks to which the gateway is directly connected to.