Routing Table 편집하기

'''Routing Table''' is a data structure used by routers to store and manage route information. It determines the best path for forwarding packets to their destination. Each entry in a routing table corresponds to a specific destination network and includes information about the next hop, metrics, and routing protocol.
==Overview==
The routing table is a fundamental component of the control plane in a network. It is built and maintained by routing protocols or through manual configuration. Routers use the routing table to make forwarding decisions and update the forwarding table in the data plane.
==Structure==
A typical routing table contains the following fields:
*'''Destination Network:''' The IP address range or subnet for the route.
*'''Subnet Mask:''' Specifies the size of the destination network.
*'''Next Hop:''' The IP address of the next router or device along the path.
*'''Metric:''' A value representing the cost of the route (e.g., hop count, delay, bandwidth).
*'''Interface:''' The local network interface to use for forwarding packets.
*'''Routing Protocol:''' Indicates the protocol (e.g., OSPF, BGP) that added the route.
Example Routing Table:
{| class="wikitable"
!Destination Network!!Subnet Mask!!Next Hop!!Metric!!Interface!!Protocol
|-
|192.168.1.0||255.255.255.0||10.0.0.1||1||eth0||OSPF
|-
|10.0.0.0||255.0.0.0||10.0.1.1||10||eth1||BGP
|-
|0.0.0.0||0.0.0.0||192.168.1.254||5||eth0||Static
|}
==Types of Routes==
Routing tables include different types of routes based on how they are learned:
*'''Static Routes:''' Manually configured by network administrators.
*'''Dynamic Routes:''' Automatically learned and updated using routing protocols (e.g., RIP, OSPF, BGP).
*'''Default Routes:''' Used when no specific match is found in the routing table; often represented as 0.0.0.0/0.
*'''Connected Routes:''' Directly connected networks that the router is aware of.
==How It Works==
#When a packet arrives, the router examines its destination IP address.
#The router searches the routing table for the most specific matching route using techniques like [[Longest Prefix Matching]].
#Once a match is found, the packet is forwarded to the next hop or local interface specified in the route.
==Dynamic Routing Protocols==
Routing tables are dynamically populated and maintained by various protocols:
*'''RIP (Routing Information Protocol):''' Uses hop count as a metric.
*'''OSPF (Open Shortest Path First):''' Calculates the shortest path using Dijkstra's algorithm.
*'''BGP (Border Gateway Protocol):''' Exchanges routing information across autonomous systems.
*'''EIGRP (Enhanced Interior Gateway Routing Protocol):''' Uses a composite metric of bandwidth and delay.
==Applications==
*'''Enterprise Networks:''' Routing tables guide traffic between different subnets and external networks.
*'''Service Providers:''' Manage large-scale routing across wide-area networks.
*'''Data Centers:''' Used to ensure efficient routing in complex, multi-tier architectures.
==Advantages==
*Provides efficient and automated routing decisions.
*Adapts dynamically to network changes using routing protocols.
*Scalable for networks of varying sizes and complexities.
==Limitations==
*Large routing tables can consume significant memory and CPU resources.
*Incorrect routing table entries can lead to routing loops or blackholes.
*Static routes require manual updates, which can be error-prone in dynamic networks.
==See Also==
*[[Forwarding Table]]
*[[Longest Prefix Matching]]
*[[Routing Protocols]]
*[[Control Plane]]
*[[Data Plane]]
[[Category:Network]]