Protocols

Part 3

2/4/2009

Questions?

• any questions?
• speed of light

Applications: Network Management

• NMS

Theory

• SMI
  • structure of management information
  • rulebook and toolkit
• MIB
  • management information base
  • layout and questionnaire
• SNMP
  • simple network management protocol
  • managers and agents
    • agents can send data to manager
    • manager can request data

RMON

• remote monitoring
  • Statistics
  • History
  • Alarms
  • Events
  • Host
  • HostTopN
  • Matrix
  • Filters
  • Packet Capture
• statistics and functions in Ethernet MIB

ISO Model

• FCAPS
  • Fault Management
  • Configuration
  • Accounting / Administration
  • Performance
  • Security

UNC Network Management

• user information tool with statistics
• the following slides as pdf, and all those with a few more in another pdf

UNC Network Management: F1

UNC Network Management: F2

UNC Network Management: C1

UNC Network Management: A1

UNC Network Management: A2

UNC Network Management: P1

UNC Network Management: P2

UNC Network Management: P3

UNC Network Management: S1

UNC Network Management: S2

Other Models

• OAMP
  • Operations
  • Administration
  • Maintenance
  • Provisioning
• Time To Call
  • monitor
  • engineer
  • manage

NAT

• Network Address Translation
• RFC 1631 obsolete, RFC 3022 traditional
  • public address routed "in front of" private addresses
    • IPv4 address are somewhat scarce
    • RFC 1918 private addresses aren't
    • aka PAT, Port Address Translation
    • remember that socket pairs are unique ...
    • but headers are modified ... so some applications like (active) ftp break

PAT

• or PAT
  • multi-homing, load balancing, failover
  • inherent incoming security
  • (inbound) port forwarding, DMZ
    • see GRC, a venerable security site
  • IPSec
  • How Skype tunnels through NAT

RFC 1918 (Review)

• private, non-routeable, addresses:
  • 10.0.0.0/8 or 10.0.0.0 to 10.255.255.255
  • 172.16.0.0/12 or 172.16.0.0 to 172.31.255.255
  • 192.168.0.0/16 or 192.168.0.0 to 192.168.255.255

Security

• authentication
• authorization
• encryption
• don't ship unencrypted private data via insecure transport (including the Internet)
• Security Engineering (book)

Privacy

• anonymity
• free speech? but SSN, voting, income
• Scott Bradner: 1 and 2

Centralized Vocabulary Review

• a centralized network is a classic tree with a single root
• a distributed network is a mesh (full or partial)
• a decentralized network is in-between

Client-Server

• centralized
• central server, many clients
• single place to update
• updates can be seen on all clients at the right time
• web, DNS, most NMS, more

Peer-to-Peer

• Wikipedia on P2P: ad hoc
• unstructured P2P
  • distributed
  • Gnutella
  • flood queries, poor traffic-to-search efficiency
• structured P2P
  • decentralized
  • CAN uses DHT, Distributed Hash Table
    • Adeona uses OpenDHT

Peer-to-Peer Discussion

• no server, but a super-node is a local server
• VoIP
  • SIP is a standard, SIP phones talk to each other directly
    • Gizmo has Google (GrandCentral) integration, free
    • QuteCom is F/OSS
  • Skype
    • P2P from Kazaa, worrisome terms

Peer-to-Peer Discussion

• where is BitTorrent?
  • tracker is a server, distribution is P2P
  • hybrid P2P
• Hamachi is zeroconf p2p vpn
  • but security
  • or just OpenVPN

Take a Deep Breath ...

IPv6 Addresses

• 128 bits written as 8 hex strings separated by colons
  • many more addresses available, not a mere 3 to 4 billion!
• leading zeroes can be omitted per string
• multiple zeroes can be omitted entirely, but only once in an address

IPv6 Features

• no broadcast

• no private addresses (but link local with low TTL)
• no DHCP (but does have automatic configuration)

• 128-bit addresses (32-bit address space is getting tight)
• less-used options in IPv4 header are now optional for less overhead
• flow-labeling for QoS
• IP Security built-in

IPv6 Header

• RFC 2460
  
• 4 bits - version (6)
• 8 bits - traffic class (priority)
• 20 bits - flow label

IPv6 Header

• 16 bits - payload length, including optional extension headers (or 0 for jumbo)
• 8 bits - next header
• 8 bits - hop limit, like TTL

IPv6 Header

• 128 bits - source address
• 128 bits - destination address

IPv6 Scope

• link local: LAN only, automatic, unrouted
• site local: optional, user assigned, unrouted
• global unicast: IANA assigned unique address
• multicast: several scopes here too ...
• anycast: one-to-nearest, routers only
• loopback: local NIC

IPv6 Multicast Scopes

• 8 bits - routing prefix (fixed)
• 4 bits - flags - 0000 for IANA or 0001 for transient
• 4 bits - scope
  • 0 & 3 & F reserved
  • 1 interface-local scope
  • 2 link-local scope
  • 4 admin-local scope
  • 5 site-local scope
  • 8 org-local scope
  • E global scope

How Do We Get There From Here?

• must translate IPv6 to IPv4
• 6to4
  • What about NAT?
    • use Teredo instead

Light Reading

• Browse Zytrax on IPv6 to supplement class coverage. Once you can handle the addressing, you're most of the way to understanding IPv6.

Homework

HW04