Static ARP Table
The
Address Resolution Protocol
(
ARP
) is a TCP/IP protocol that converts IP addresses into physical addresses.This table allows network managers to view, define,
modify and delete ARP information for specific devices.
Static entries can be defined in the
ARP Table
.When static entries are defined, a permanent entry is entered and is used to translate IP address to MAC
addresses.
To open the
Static ARP Table
open the
Configuration
folder, and then open the
Layer 3 IP Networking
folder and click on the
Static ARP
Table
link.
Figure 6- 93. Static ARP Settings window
To add a new entry, click the
Add
button, revealing the following screen to configure:
Figure 6- 94. Static ARP Table – Add a New Entry window
The following fields can be set:
Parameter
Description
IP Address
The IP address of the ARP entry.
MAC Address
The MAC address of the ARP entry.
After entering the IP Address and MAC Address of the
Static ARP
entry, click
Apply
to implement the new entry.To completely clear the
Static ARP
Settings
, click the
Clear All
button.To delete an entry located in the Static ARP Settings window, click the corresponding
8
under the
Delete
heading.
RIP
The Routing Information Protocol is a distance-vector routing protocol.There are two types of network devices running RIP – active and passive.Active devices
advertise their routes to others through RIP messages, while passive devices listen to these messages. Both active and passive routers update their routing tables
based upon RIP messages that active routers exchange. Only routers can run RIP in the active mode.
Every 30 seconds, a router running RIP broadcasts a routing update containing a set of pairs of network addresses and a distance (represented by the number of
hops or routers between the advertising router and the remote network). So, the vector is the network address and the distance is measured by the number of
routers between the local router and the remote network.
RIP measures distance by an integer count of the number of hops from one network to another.A router is one hop from a directly connected network, two
hops from a network that can be reached through a router, etc.The more routers between a source and a destination, the greater the RIP distance (or hop
count).
There are a few rules to the routing table update process that help to improve performance and stability.A router will not replace a route with a newly learned
one if the new route has the same hop count (sometimes referred to as ‘cost’). So learned routes are retained until a new route with a lower hop count is
learned.
When learned routes are entered into the routing table, a timer is started.This timer is restarted every time this route is advertised. If the route is not
advertised for a period of time (usually 180 seconds), the route is removed from the routing table.
RIP does not have an explicit method to detect routing loops. Many RIP implementations include an authorization mechanism (a password) to prevent a router
from learning erroneous routes from unauthorized routers.
100
Allied Telesyn AT-9724TS High-Density Layer 3 Stackable Gigabit Ethernet Switch
