CSEE W 4140 Networking Laboratory Lecture 12 Review

CSEE W 4140 Networking Laboratory Lecture 12: Review Jong Yul Kim 04. 22. 2009

Annoucements o Visit to Telio. Sonera’s NY POP n Meet in front of Broadway and 116 th st main gate at starting time. n Wednesday group: 1 pm Friday group: 10 am n Can you join the Friday group? n

ICANN o Internet Corporation for Assigned Names and Numbers

IANA o Is run by ICANN o Provides global coordination of n n Domain names (manages root) IP addresses AS numbers Protocol assignments

Registry Listings from ICANN TLD Introduced Sponsored/ Unsponsored . com 1985 Unsponsored Unrestricted (but intended for commercial registrants) Veri. Sign, Inc. Registry Customer Service Veri. Sign Naming Services 21345 Ridgetop Circle Dulles, Virginia 20166 United States Tel : +1 703 925 -6999 Fax: +1 703 421 -5828 http: //www. verisigngrs. com . net 1985 Unsponsored Unrestricted (but intended for network providers, etc. ) Veri. Sign, Inc. Registry Customer Service Veri. Sign Naming Services 21345 Ridgetop Circle Dulles, Virginia 20166 United States Tel: +1 703 925 -6999 Fax: +1 703 421 -5828 http: //www. verisigngrs. com . edu 1985 Sponsored United States educational institutions EDUCAUSE Becky Granger EDUCAUSE 4772 Walnut Street, Suite 206 Boulder, Colorado 80301 United States Tel: +1 -303 -939 -0334 Fax: +1 -303 -440 -0461 http: //www. educause. edu/ edudomain Purpose Sponsor/ Operator Contact

Regional Internet Registries (RIRs) o o o Registration and management of IP address is done by Regional Internet Registries (RIRs) Where do RIRs get their addresses from: IANA maintains a high-level registry that distributes large blocks to RIRs RIR are administer allocation of: n IPv 4 address blocks n IPv 6 address blocks n Autonomous system (AS) numbers

Regional Internet Registries (RIRs)

Tiered hierarchy of ISPs

Tier-1 ISPs o o Tier-1 ISPs form the backbone of the Internet Directly connected to each other for free: this is called peering. Tier-2 ISPs and other networks connect to them for a fee: this is called transit. International presence Name AS # AT&T 7018 Global Crossing 3549 Level 3 Communications 3356 NTT Communications 2914 Qwest 209 Sprint 1239 Tata Communications 6453 Verizon Business 701 SAVVIS 3561 Telia. Sonera IC 1299

What happens if Tier-1 ISPs fight each other? o Excerpts from “Sprint, Cogent in Peering Feud” by Karl Bode as published in dslreports. com. n n “A high profile dispute with Swedish telecom operator Telia in March cut off access to vast swaths of Europe. ” “The latest fight came last night, when Cogent announced that Sprint pulled the plug on their connection with the Cogent network, impacting a significant amount of both URLs and broadband customers. ”

Point-of-Presence (POP) o o o A location where ISPs interconnect with each other. Usually houses a group of routers and switches that are shared among the ISPs. Also known as Internet Exchange Points (IXP)

Routing Protocols o BGP for interdomain routing o RIP and OSPF for intradomain routing n n n RIP is a distance vector protocol. Count-to-infinity is a problem. There are ways to deal with the problem. OSPF is a link state protocol. All routers have the same routing information. Unless they are divided into two-level hierarchy called areas.

LAN and switches o In setting up a LAN, you can use routers, hubs, and switches. n n o Routers vs. switches Hubs vs. switches Switches have nice properties. n n Plug-and-play through learning algorithm Spanning Tree Protocol to avoid loops

IP addressing and subnets o IP addresses n n o have two parts: prefix and host. (CIDR notation: 10. 0. 2. 0/24) Prefixes are used by routers to forward packets to the correct destination Subnets n n n Are divided by routers and hosts. Every machine in a subnet uses the same prefix. What happens if a machine’s netmask is different from the subnet’s prefix?

ARP o o ARP is used to find the MAC address of the machine that uses a particular IP address. ARP is used within a subnet. n o Unless a router uses proxy ARP to forward ARP requests to another subnet. There are many other uses of ARP. n n IP conflict detection RARP for IP address configuration

NAT and DHCP o NAT n n is an outcome of the shortage of IPv 4 addresses. But they can be used in many different applications, e. g. support migration between service providers. o NAT can be problematic for some applications. o DHCP is used to configure hosts within a subnet automatically. n Relays can be used to traverse subnets.

SNMP o o o SNMP is used for network management. The information objects are structured as a tree. (OID reflects the tree structure. ) Four parts: MIBs, SMI, the protocol, and security.

Homework o o No prelabs due this Friday Lab report 9 due next week by the normal dates