Transcript File

Group project Sept 23
Page 322, Review Questions.
Explain your answers! Not just one word or letter.
Write a few sentences on why/how.
Question numbers 12, 13, 14, 15
Bonus Questions: 1. Describe a situation when
OSPF can result in faster routing than RIP.
2. Is there ever a situation in which you would
use RIP instead of OSPF? If yes, why? If no,
why not?
Chap 7: Wrapping Up
-Odds and ends
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•
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Simplex, Half-Duplex, Full-Duplex
Switch Security
DHCP
Naming
-The Full Story
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How traffic is routed
Chap 7: Communication
Chap 7: Switch security
VLANs – provide isolation
Port Security – restrict which/how many MAC
addresses can use the port
Chap 7: Dynamic Host
Configuration Protocol
DHCP has a “pool” of available IP address
When a host starts up, it broadcasts asking for a
DHCP server (why doesn't it unicast?)
The server responds by giving the host an IP
address, subnet mask, and default
gateway(which is usually the router)
Chap 7: DHCP
Chap 7: Naming
MAC address is sometimes called a “PHYSICAL
ADDRESS”
•
•
“Who did it PHYSICALLY come from?”
“Who is it PHYSICALLY going to?”
IP address is sometimes called a “LOGICAL
ADDRESS”
•
•
“Who did it LOGICALLY(originally) come from?”
“Who is it LOGICALLY(eventually) going to?”
Chap 7: Naming
MAC address is sometimes called a “PHYSICAL
ADDRESS”
•
•
“Who did it PHYSICALLY come from?”
“Who is it PHYSICALLY going to?”
IP address is sometimes called a “LOGICAL
ADDRESS”
•
•
“Who did it LOGICALLY(originally) come from?”
“Who is it LOGICALLY(eventually) going to?”
Chap 7: The Full Story
Chap 7: The Full Story
Sender determines that the IP address of
recipient is not on his own network (How?)
Sender discovers default gateway's (a.k.a. the
router) MAC address (How?)
Sender sends data to the default gateway
(router's MAC address, receiver's IP address)
Chap 7: The Full Story
Chap 7: The Full Story
Router receives the data, checks the frame to
see if destination MAC address is the router.
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(it is)
Router de-encapsulates and checks the packet
to see if the IP address is is the router
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(it isn't, it's the IP address of the final
destination)
Router checks its routing table to see if it knows
about the destination network
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(it does, the network is directly connected)
Chap 7: The Full Story
Chap 7: Naming
MAC address is sometimes called a “PHYSICAL
ADDRESS”
•
•
“Who did it PHYSICALLY come from?”
“Who is it PHYSICALLY going to?”
IP address is sometimes called a “LOGICAL
ADDRESS”
•
•
“Who did it LOGICALLY(originally) come from?”
“Who is it LOGICALLY(eventually) going to?”
Chap 7: The Full Story
Router re-encapsulates data into new packet...
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•
•
Source MAC=Router's MAC address (which
one?)
Dest MAC=Receiver's MAC address
Source and Dest IP addresses do not change
...and forwards the packet to the receiver.
Chap 7: The full story
5 minute break
Chap 7: RIP Review
Rip is a DISTANCE VECTOR dynamic routing
protocol.
It uses HOP COUNT as its metric. (Directly
connected networks have a metric of 0. Why?)
Routers running RIP periodically send out their
full routing table.
Routing entries look like this:
DESTINATION, NEXTHOP,METRIC, EXIT
INTERFACE
Group proj 9-28 – RIP Routing table
In groups of up to 5 people:
Page 327 Challenge Lab 7-2
Fill in the routing tables for routers A,B,C, and D
BONUS (review) QUESTIONS:
1. What are the first three bytes of a MAC
address called?What purpose do they serve?
2. Why do we call each decimal-separated
section of an IPv4 address in dot-decimal
format an “octet”?