WANs

1
WANs

• 1. A customer has 5 sites that are to be
  connected in a WAN. On a separate piece of
  paper, raw the network for each of the following
  scenarios (label equipment)
• a. A private T1 network Star topology.
• b. A private T1 network Full Mesh topology.
• c. The customer uses a public Frame Relay
  network Full Mesh PVC topology.
• 2. Leda Company has a campus network comprising
  one router that connects three 10/100 switches,
  plus has one WAN interface to the Internet. The
  company has a T3 to the Internet.
• a. There are a total of 500 users on the
  network. At the busiest hour of the day, each
  user receives around 20 MB of data from the
  Internet. What is the utilization of the
  Internet connection during the busy hour?
• b. What protocols are being used in the campus
  and across the WAN link?
• Intra-Campus Across the WAN Link
  (Router to ISP)
• Layer 1

2
For questions on next page
All located in Northern Virginia
Local Communications Company (e.g., Verizon)
Northern VA. POP
Sue Home Phone Modem
Internet (Collection of IP networks
inter- connected)
Sam Co. Site 1
R
ISP POP
100BaseT Switch
ISP POP
LAN
Johns Home Phone Modem
Sam Co.Site 2
Atlanta POP
R
R
100BaseT Switch
100BaseT Switch
LAN
www.sam.com
Located in Atlanta
3
ExercisesWhere it says describe the switching
answer the followingWhere is the traffic being
circuit-switched? Where is it being
packet-switched?Where is NOT being switched at
all?(keep in mind not applicable is an
appropriate answer to some switching questions)

• Place a phone call between the homes
• What service is being used?
• Describe the switching (see above)
• Sam Co. wants a private WAN with a transmission
  rate of at least 1 Mbps between its two sites
• Draw the private WAN.
• What service is being used?
• Describe the switching (see above)
• Sam Co. sees that it has under-estimated the
  traffic between its sites, causing a bottleneck.
  What can Sam Co. do?
• Sam Co. wants to enable anyone to view its
  company / marketing information, so it installs a
  web server and builds web pages. Sam Co. now
  needs to make the web server publicly available
  so it orders a T1, domain name and static IP
  address from an ISP.
• Draw the T1. Describe the switching and
  protocols.
• John pays 20/month for Internet Service. He
  wants to access www.sam.com. Can he? If so,
  draw the connection.
• What service(s) are being used?
• Describe the switching and protocols.
• John now wants to access the Sam Co. LAN at site
  2. Can he? If so, draw the connection. If not,
  why not?
• Employees at Sam Co. Site 1 want to access the
  Internet. Can they?
• Employees at Sam Co. Site 2 want to access the
  Internet. Can they?
• If you build connections such that employees in
  Sam Co. Site 2 can access the Internet, does this
  mean that John can access the Sam Co. Site 2 LAN?
• Instead of a Private WAN, Sam Co. orders Frame
  Relay service from Verizon to connect its two
  sites. It also uses Frame Relay to connect its
  web server to the Internet and users at each site
  to the Internet (assume a separate PVC for the
  web server).
• On a separate sheet of paper, draw the network.
  Describe the protocols.

4
ROUTER LINE CARDS
Sam Co. has 4 sites, each with 1 Ethernet LAN.
B
A
C
D

• 1. He builds a T1 WAN, Star Topology.
• Draw the network, including the routers.
• Configure the routers (i.e., of slots required
  on each router? Line cards needed?)
• Sam Co. wants to use a T1 WAN, Full Mesh Topology
  instead.
• Draw the network, including the routers.
• Configure the routers (i.e., of slots required
  on each router? Line cards needed?)