CSE 3901 FINAL COMPLETE PREPARATION
GUIDE WITH OBJECT-ORIENTED DESIGN,
TESTING, AND DEPLOYMENT REVIEW
◉ Forwarding.
Answer: Move packets from router's input to appropriate router
output
◉ Routing.
Answer: Determine route taken by packets from source to dest
◉ Datagram network.
Answer: A true packet switched network. There is no fixed path for
transmitting data. The individual packets which form a data stream
may follow different paths between the source and the destination.
As a result, the packets may arrive at the destination out of order.
◉ Virtual Circuit.
Answer: Uses a fixed path for a particular session, after which it
breaks the connection and another path has to be set up for the next
session. Generally packets are in order.
◉ VC overview.
,Answer: "source-to-dest path behaves much like telephone circuit"
performance wise
network action along source-to-dest path
Call setup, teardown for each call before data can flow
Each packet carries VC identifier ( not destination host address)
Every router on source-dest path maintains "state" for each passing
connctione
Link, router resources (bandwidth, buffers) may be allocated to VC (
dedicated resources= predictable service)
◉ VC implementation.
Answer: VC consists of:
1. path from source destination
2. VC numbers, one number for each link along path
3. Entries in forwarding tables in routers along path
packet belonging to VC caries VC number
◉ VC signaling protocols.
Answer: used to setup, maintain teardown VC
used in ATM, frame-relay, X.25
,not used in today's INternet
1. Initiate call
2. Incoming call
3. Accept Call
4. Call connected
5. Data flow begins
6. Receive data
◉ VC Forwarding Table.
Answer: Router maintains connection state information
◉ Datagram networks.
Answer: no call setup at network layer
routers: no state about end-to-end connections
no network-level concept of "connection"
packets forwarded using destination host address
packets between same source-dest pair may take
different paths
1. Send data
, 2. Receive data
◉ Datagram forwarding
table.
Answer: IP destination address in
arriving packet's header
◉ Longest prefix matching.
Answer: when looking for forwarding table entry for given
destination address, use longest address prefix that
matches destination address.
◉ Datagram or VC network: why?.
Answer: Datagram (e.g., Internet)
❒ "Dumb" core.
❒ "Smart" end systems.
❒ Datagrams are selfcontained
and independent
from one another.
❒ No need for setting up
connection (virtual circuit).
GUIDE WITH OBJECT-ORIENTED DESIGN,
TESTING, AND DEPLOYMENT REVIEW
◉ Forwarding.
Answer: Move packets from router's input to appropriate router
output
◉ Routing.
Answer: Determine route taken by packets from source to dest
◉ Datagram network.
Answer: A true packet switched network. There is no fixed path for
transmitting data. The individual packets which form a data stream
may follow different paths between the source and the destination.
As a result, the packets may arrive at the destination out of order.
◉ Virtual Circuit.
Answer: Uses a fixed path for a particular session, after which it
breaks the connection and another path has to be set up for the next
session. Generally packets are in order.
◉ VC overview.
,Answer: "source-to-dest path behaves much like telephone circuit"
performance wise
network action along source-to-dest path
Call setup, teardown for each call before data can flow
Each packet carries VC identifier ( not destination host address)
Every router on source-dest path maintains "state" for each passing
connctione
Link, router resources (bandwidth, buffers) may be allocated to VC (
dedicated resources= predictable service)
◉ VC implementation.
Answer: VC consists of:
1. path from source destination
2. VC numbers, one number for each link along path
3. Entries in forwarding tables in routers along path
packet belonging to VC caries VC number
◉ VC signaling protocols.
Answer: used to setup, maintain teardown VC
used in ATM, frame-relay, X.25
,not used in today's INternet
1. Initiate call
2. Incoming call
3. Accept Call
4. Call connected
5. Data flow begins
6. Receive data
◉ VC Forwarding Table.
Answer: Router maintains connection state information
◉ Datagram networks.
Answer: no call setup at network layer
routers: no state about end-to-end connections
no network-level concept of "connection"
packets forwarded using destination host address
packets between same source-dest pair may take
different paths
1. Send data
, 2. Receive data
◉ Datagram forwarding
table.
Answer: IP destination address in
arriving packet's header
◉ Longest prefix matching.
Answer: when looking for forwarding table entry for given
destination address, use longest address prefix that
matches destination address.
◉ Datagram or VC network: why?.
Answer: Datagram (e.g., Internet)
❒ "Dumb" core.
❒ "Smart" end systems.
❒ Datagrams are selfcontained
and independent
from one another.
❒ No need for setting up
connection (virtual circuit).
