Network Design and Management

• CIS 5930-6 CIS 4930-7

• Mike Sloderbeck

• Ray Curci• http://www.cs.fsu.edu/courses/netdesign

• Change to syllabus:

• quiz/participation now 20%

• assignments now 40%

Is this the right class for you?

• Network class prereq (or permission)

• Are these terms familiar?

• TCP, UDP, CSMA/CD, DNS

• We won’t cover much of this, but you need to to know these things, so....

• Not heavily research-oriented

What We Will Cover

• IP Addresses, Masks and Networks (Class-ful addressing),The Routing Process, Network Matching, Prefix length,Subnet Masks and Hosts per subnet, Subnets other than /24, ARP, Bridges, Switches and VLANS, Typical Physical Networks, especially ones on the lab routers: ethernet, synchronous serial, FDDI, T1 basics, CSU/DSU, Wireless networks

• SNMP (in detail) agent, management station, community, SMI, MIB, ASN.1,data object naming, MIB Tree, agent commands, commandline tools (snmpget, snmpwalk, snmpset, snmpnetstat), MRTG views, Cisco SNMP router syntax,Using SNMP tools for network topology discovery

• Static Routes,Routing tables,Requirements for Routing Protocols

• RIP version 1 (in detail) debug, monitor via ethereal/tcpdump, hop counts, poison reverse, split horizon,

Classless Addresses, Variable Length Subnet Masks (VLSM),Network Design with VLSM, Software tools for performance testing (iperf, traceroute, ping)

• RIP version 2• OSPF (in detail) hello, neighbor, adjacency, link state

advertisement (LSA), designated router (DR), backup designated router (BDR), link state database, Dijkstra SPF algorithm, multiple area networks, area 0

• Route Redistribution between protocols, Route Filtering, Route Maps, Internet Service Providers and access, ARIN, Commercial peering,Transit, Private peering

BGP (in detail), EBGP, IBGP, Autonomous System, AS Path, AS Path Prepending, Local Preference, AS Path Filtering, Hot Potato routing,

Cisco Access Lists

More or less, in one term.

An Idealized Address

• “r” bits long (r = p + q)

• “p” bits of network id

• “q” bits of host id

• Example, r=11, p=5, q=6

• How many networks? Hosts per net?

An Idealized Address

• Example, r=11, p=5, q=6

• How many networks?

• How many hosts per network?

• 32 networks, 64 hosts per network

• (IP conventions allow fewer)

Novell Address

• 8 bytes of network id

• 6 bytes of host id (uses MAC)

• 64 + 48 bits

• fixed p,q

IP v4 as an Ideal Address

• r is fixed at 32 bits

• p and q are (ideally) variable

• If p is 8, 16, or 24, this suggests the Class A, Class B, Class C addresses

• For these classes, however, we also restrict the numbering

Class Restrictions

• A addresses begin in 0

• B addresses begin in 10

• C addresses begin in 110

Class Restrictions

• 0, 10, 110, ??

• But you were probably hoping for the familiar, (in)convenient, and dreaded “dotted decimal”

• You’ll be sorry...

Classes Reviewed

• 1-126.x.y.z (0 and 127 reserved)

• 128-191.X.y.z (X is part of the net id)

• 192-223.X.Y.z (X and Y part of net id)

• D, E

• lots of waste

Subnets

• Specify p -- the network mask

• p > 8 in the class A space, or

• p > 16 in the class B space (FSU),

• p > 24 in the class C space

• But leave some bits for host ID !!

Supernets

• p < 8 in the class A space, or

• p < 16 in the class B space

• p < 24 in the class C space

Subnets, cont

• FSU subnets 128.186.0.0 with a 24 bit mask (255.255.255.0 or /24)

• 128.186.17.0 and 128.186.121.0 are different networks (data link layer)

• But you don’t have to use a 24 bit mask to subnet a class B

• IP Subnetting defined in 1984• Useful in large, bridged class B nets and to

conserve IP addresses• Expressed as dotted decimal or /nn notation• 128.186.121.1 /24 is the same as

128.186.121.1 255.255.255.0• 192.168.1.1 /28 is the same as 192.168.1.1

255.255.255.240

Network Matching

• Use the network mask• Bit-wise compare the two networks, using the

mask length• 192.168.1.2 /28 and 192.168.1.250 /28 are

on different networks (or different subnets, if you prefer that terminology).

• 192.168.1.2 /28 and 192.168.1.3 /28 are on the same subnet. (use the data link)

Network Masks

• Note that network masks work for classful network matching also.

• 128.186.234.2 /16 and 128.187.123.4 /16 must be on different networks when the first 16 bits of the addresses are compared.

• Modern IP routing tables include a mask for every network route.

Host Addresses per Network

• The lowest address refers to the network itself and can’t be used for a host. Eg. 192.168.1.0 /24

• The highest address is reserved for the IP broadcast address. Eg. 192.168.1.255 /24

• So in this network there are 254 available IP addresses for hosts and routers.

Host Addresses in a Subnet

• The address 192.168.1.16 /28 refers to the network and can’t be used for a host.

• The address 192.168.1.31 /28 is reserved for the IP broadcast address.

• This network has 14 IP addresses available for hosts and routers.

Examples

• Subnet 172.17.0.0 so that each subnet has at least 700 host addresses

• Subnet 192.168.100.0 so that each subnet has two usable host addresses

• How many subnets of the original network are obtained in each case?

• Review Doyle, Fig 2.16, 2.17, 2.18