Transcript Routing Information Protocol 2 (RIP2)

Routing Information Protocol 2
(RIP2)
Study_Group_208
Shrotri Meghana
Dhar Aparna
Narkar Priyanka
Dulam Vasundhara
Mondedula Kalyani
Agenda
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RIP Overview, History and Versions
RIP2 over RIP1
Configuring RIP and RIP commands
Distance Vector Algorithms and count to
infinity problem
Protocol Specification and Message Format
Addressing Considerations
Timers, Input and Output processing
Security considerations in RIP2
What is RIPng advantages and usage
Disadvantages of RIP2 and proposed
solutions
Conclusion
RIP Overview, History and Versions
An interior gateway protocol (IGP),
which means that it performs routing
within a single autonomous system
(Exterior: BGP)
 The original incarnation of RIP was
the Xerox protocol
 AppleTalk Routing Table Maintenance
Protocol (RTMP) and the Banyan
VINES Routing Table Protocol (RTP),
these are based on the versions of
RIP
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Advantages of RIP and Disadvantages of RIP1
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Advantages of RIP:
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RIP is very useful in a small network, where it has very little
overhead in terms of bandwidth used and configuration and
management time.
Easy to implement than newer IGP’s
Many implementations are available in the RIP field.
Disadvantages of RIP1:
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minimal amount of information for router to route the packet
and also very large amount of unused space.
Subnet support : Supports subnet routes only within the
subnet network
Not secure; anyone can act as a router just by sending RIP-1
messages
RIP1 was developed for an AS that originally included less
than a 100 routers
RIP2
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Latest version of RIP, RFC: 2453,Build in 1990
Advantages:
– An AS can include several hundred routers with RIP-2
protocol.
– Compatible upgrade of RIPv1 including subnet routing,
authentication, CIDR aggregation, route tags and
multicast transmission
– Subnet Support : uses more convenient partitioning
using variable-length subnets
– An end system can run RIP in passive mode to listen for
routing information without supplying any.
– Low requirement in memory and processing at the node
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RIP and RIP2 are for the IPv4 network while the
RIPng is designed for the IPv6 network.
RIP Message Transfer
AS
128.10 Network
SUB Netted network
Routing Table
S1
130.10.62.2
S0
130.10.65.1
R
IP
RI
P
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Me
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ss
sa
ag
es
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S5
130.10.65.5
Routing Table
128.6 Network
SUB Netted network
S2
130.10.62.3
S3
130.10.64.3
S4
130.10.64.4
s
RIP Message
Routing Table
128.8 Network
SUB Netted network
Practical use in Yahoo Chat IM
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Routing information protocol: gives
command, version ip domain and
address information.
RIP Configuring and Commands
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ip routing : enables the router
router rip : you can enter configuration
commands to define the RIP process for
router
network network_address : Telling the
router which networks it should advertise
routes for
write, write terminal : Saving configuration
& view currently running configuration
ping address : To check and see if the
packets are getting routed
show ip route : To view the routers current
routing table
show ip rip ? : Gives information about RIP
Distance Vector Protocol
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Compatible upgrade of RIPv1 including subnet routing,
authentication, CIDR aggregation, route tags and multicast
transmission
Subnet support: RIPv1 supports subnet routes only within the
subnet network while RIPv2 includes subnet mask in the
messages. This allows for subnet knowledge outside subnet. More
convenient partitioning using variable length subnet.
RIPv2 is a distance vector based routing protocol. RIP2 supports
variable-length subnet masks (VLSM).
Distance vector routing protocols: Distance-based vector routing
protocols base the optimal route on the number of hops (i.e.,
devices) a packet must pass through to reach a destination.
 Neighboring nodes send information in regular time intervals
 Install routes directly in tables, lowest cost wins
 The information sent (the distance vectors) are all routes
from the table
The shortest path tree is contained in the routing table
Calculations are based on the Bellman-Ford algorithm
Potential Problems and Solutions
Potential Problems:
– Count to infinity problem
– Routing loops
SOLUTION: Triggered Updates/Split Horizon for Preventing Two-hop Loops
Split Horizon:
"Split horizon" is a scheme for avoiding problems caused by including routes in
updates sent to the router from which they were learned.
– Simple - The information about destination routed on the link is omitted
– With poisonous reverse -The corresponding distance is set to infinity if
the destination is routed on the link
Triggered updates:
– Split horizon with poisoned reverse will prevent any routing loops that
involve only two routers. However, it is possible to end up with patterns
in which three routers are engaged in mutual deception.
– A timer is associated with each entry in the routing table - much longer
than the period of transmission of information
– Triggered updates request nodes to send messages as soon as they
notice a change in the routing table
RIP 2 Packet Format
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Command -- The command field is used
to specify the purpose of the datagram.
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Version -- The RIP version number. The
current version is 2.
Protocol Structure - RIP & and RIP2: Routing Information Protocol
Max pkt size 512
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http://www.colasoft.com/resources/protocol.php?id=RIP2
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Address family identifier -- Indicates
what type of address is specified in this
particular entry.
Route tag -- Attribute assigned to a
route which must be preserved and
readvertised with a route. The route tag
provides a method of separating internal
RIP routes from external RIP routes,
which may have been imported from an
EGP or another IGP.
IP address -- The destination IP
address.
Subnet mask -- Value applied to the IP
address to yield the non-host portion of
the address. If zero, then no subnet
mask has been included for this entry.
Next hop -- Immediate next hop IP
address to which packets to the
destination specified by this route entry
should be forwarded.
Metric -- Represents the total cost of
getting a datagram from the host to that
destination.
RIPv2 Packet Format (With/Without Authentication Header)
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RIPv2 packet with no Authentication
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RIPv2 packet with Authentication
header
Example and Routing Table Structure
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Included in RIP routing table
-Address of (net/subnet/host) destination
-Metric associated with destination
-Address of next hop router
-Recently updated flag
-Several timers
IP Routing table for Router R1
RIP2 Extensions
 authentication
 routing
per subnet
 support of multiple metrics
 routing domains
 multicasting
Addressing Consideration
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IP address field in RIP2
message (Request/ Response )
format can be networks,
hosts, or a special code
used to indicate a default
address - example
AS
128.10 Network
SUB Netted network
Routing Table
S1
130.10.62.2
ges
RIP
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Subnet addresses must not
be sent outside the network
of which the subnet is a
part.
0.0.0.0 is used to describe a
default route.
es
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S0
130.10.65.1
PM
RI
– 128.6
Network Address
– 128.6.4.1
Host
address
– 0.0.0.0
Default address
S5
130.10.65.5
Routing Table
128.6 Network
SUB Netted network
S2
130.10.62.3
S3
130.10.64.3
S4
130.10.64.4
RIP Messages
Routing Table
128.8 Network
SUB Netted network
Timers
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Multiple timers for performance regulation
Each route contains the following timers.
– Routing-update timer.
–--- 30
Seconds
 Every 30 seconds, the output process is
instructed to generate a complete
response to every neighboring
router/gateway.
 30 seconds updates are triggered by a
clock not affected system load or
service.
 To prevent collisions – 30 second timer
offset by addition of a small random
time.
Timers
– Time out timers. ---- 180 Seconds
 Set route metric to 16 (Infinity);
 Route change flag is set
 The output process is instructed to
generate a response message (Notify
neighbors).
– Garbage collection timer. ----- 120
Seconds
 Route is deleted from routing table.
 The output process is instructed to
generate a response message (Notify
neighbors).
Initialization
 Initialization
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This is done when host first comes online.
Determine who the neighbors are.
Set command field to 1
Send request for entire routing table from
neighbors.
Operations - Input Processing
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Handles the datagram received on RIP port (520).
Do validation ( such as version number etc)
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If validation fails log the error
Check command field (Request or Response)
Handling Input Request Message–
– Initialization Request
-- Send entire routing
table.
– Specific request
-- Send only entries
requested.
– Send response immediately
Handling Input Response Message- A response can be
received for one of several following reasons.
– Response to a specific query (direct UDP connection
for the router).
– Regular update (Unsolicited response).
–
Triggered update caused by a route change.
RIP Response Message
Operations – Output Processing
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Describes the processing used to create response and
request messages.
The out put processing is triggered by the following
ways.
– By input processing
– By regular routing update ( broadcast/multi cast at
every 30 secs)
– By the triggered updates ( When a route changes)
Generating Request Message
– Can send one Request
– Request for entire routing table.
Generating Response Messages
– Response to Request
 Sent to only one destination
– Regular updates
 Send the entire routing table
– Triggered Updates
 Create Response messages to neighbors.
Interaction between RIPV1 and
RIPV2
 Limiting
Networks
 Disable Auto-Summarization
 Single Subnetmask
Security Considerations
 Authentication
1. Plaintext Authentication
Algorithm
2.Cryptographic
Authentication
1.Keyed Message Digest 5
2.HMAC-SHA1
 Peer Security
 Router Filters
RIPng
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IPv6 compatible version of RIP
complete new protocol
Uses distance vector algorithm
Uses standard port nuber 521 and runs over
UDP
Installs the best route in the RIPng routing
table
RIPng v/s RIP-2
RIPng
RIP-2
Learns IPv6 route
information
Learns IPv4 route
information
Uses port number 521.
Uses port number 520
Requires no
Requires authentication
authentication for RIPng for RIP protocol packets
protocol packets.
No support for multiple
instances of RIPng.
Support for multiple
instances of RIP-2
RIP2 - Disadvantages
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RIP-2 supports generic notion of
authentication, but only “password” is
defined so far. Still not very secure.
RIP2 packet size increases as the number of
networks increases hence it is not suitable
for large networks.
RIP2 generates more protocol traffic than
OSPF, because it propagates routing
information by periodically transmitting the
entire routing table to neighbor routers
RIP2 may be slow to adjust for link failures.
Solution:OSPF within an AS
Can support fine-grained metrics (vs.
RIP)
 Multiple metrics
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– Throughput, Delay, Cost, Reliability
Can compute a different routing table
for each metric.
 OSPFv2 supports an extension that
allows the metric to be used specified
in the packet.
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Conclusion
RIP2 offers many substantial features
used to increase the efficiency of
RIP1
 RIP2 have one negative feature of
RIP1 - the path between two subnets
is based on the fewest number of
router hops
 RIPng is a complete new protocol
designed for Ipv6. It uses the same
operations as that of RIP1 and RIP2
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References
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<http://www.pmg.com/otw_nwsl/97_w_rip1.htm>
<http://www.javvin.com/protocolRIP.html>
<http://www.colasoft.com/resources/protocol.php?id=RIP2>
<http://www.protocols.com/pbook/tcpip4.htm>
<http://www.soi.wide.ad.jp/soi-asia/pkg1/06/43.html>
<http://www.cs.berkeley.edu/~kfall/EE122/lec16/sld010.htm
>
<http://www.uniar.ukrnet.net/tcpip/crhbook/chap04.html>
<http://www.faqs.org/rfcs/rfc2453.html>
<http://www.faqs.org/rfcs/rfc1723.html>
<http://www.faqs.org/rfcs/rfc1058.html>
<http://www.cs.odu.edu/~sudheer/technical/presentations/In
troductionToRIP2.pdf>
http://www.networkdictionary.com/protocols/rip.php?PHPSES
SID=c2a79111d168faf
http://www.tcpipguide.com/free/t_RIPOverviewHistoryStanda
rdsandVersions.htm
http://www.cisco.com/univercd/cc/td/doc/product/software/i
os121/121cgcr/ip_c/ipcprt2/1cdrip.htm
http://www.duke.edu/~yy7/ee156/rip.htm
Questions???