Global Information Systems and Software Technology (GISST)
Download
Report
Transcript Global Information Systems and Software Technology (GISST)
University of British Columbia
CICS 515 (Part 2) Computer Networks
Lecture 5b-c – IPv6 and Other Protocols
Instructor: Dr. Son T. Vuong
Email: [email protected]
The World Connected
Cics 515 – Summer 2012 © Dr. Son Vuong
1
IPv6
Initial motivation: 32-bit address space soon to
be completely allocated.
Additional motivation:
header
format helps speed processing/forwarding
header changes to facilitate QoS
IPv6 datagram format:
fixed-length 40 byte header
no fragmentation specified in basic header
Cics 515 – Summer 2012 © Dr. Son Vuong
2
IPv6 Header (Cont)
Priority: identify priority among datagrams in flow
Flow Label: identify datagrams in same “flow.”
(concept of“flow” not well defined).
Next header: identify upper layer protocol for data
Cics 515 – Summer 2012 © Dr. Son Vuong
3
Other Changes from IPv4
Checksum: removed entirely to reduce
processing time at each hop
Options: allowed, but outside of header,
indicated by “Next Header” field
ICMPv6: new version of ICMP
additional
message types, e.g. “Packet Too Big”
multicast group management functions
Cics 515 – Summer 2012 © Dr. Son Vuong
4
Transition From IPv4 To IPv6
Not all routers can be upgraded simultaneous
no
“flag days”
How will the network operate with mixed IPv4 and
IPv6 routers?
Tunneling: IPv6 carried as payload in IPv4
datagram among IPv4 routers
Cics 515 – Summer 2012 © Dr. Son Vuong
5
Dual
IPv6/IPv4
Router
Tunneling
Logical view:
Physical view:
Dual
IPv6/IPv4
Router
A
B
IPv6
IPv6
A
B
C
IPv6
IPv6
IPv4
Flow: X
Src: A
Dest: F
data
A-to-B:
IPv6
Cics 515 – Summer 2012 © Dr. Son Vuong
E
F
IPv6
IPv6
D
E
F
IPv4
IPv6
IPv6
tunnel
Src:B
Dest: E
Src:B
Dest: E
Flow: X
Src: A
Dest: F
Flow: X
Src: A
Dest: F
data
data
B-to-C:
IPv6 inside
IPv4
B-to-C:
IPv6 inside
IPv4
Flow: X
Src: A
Dest: F
data
E-to-F:
IPv6
6
IPv6 – Peer Instruction – Question 5.2
IPv6 supports the following features:
A. 128-bit IP address
B. Auto-configuration (plug-and-play) (stateless)
as well as dynamic IP address via a DHCPv6
server (stateful)
C. More options via extension headers
including Jumbogram of greater than 64KB
D. Efficient header processing
E. All the above
F. A, B and C
Cics 515 – Summer 2012 © Dr. Son Vuong
7
IPv6 – Peer Instruction – Question 5.3
An IPv6 datagram is 80,000 bytes. What extension
header must be used?
A. Destination option
B. Fragmentation
C. Authentication
D. Hop-by-hop
E. None of the above
Cics 515 – Summer 2012 © Dr. Son Vuong
8
IPv6 – Peer Instruction – Question 5.4
The IPv6 jumbogram option gives rise to the
following issues:
A. Fragmentation
B. 16-bit length of UDP
C. 16-bit MSS option of TCP
D. Checksum calculation
E. All of the above
F. B and C
Cics 515 – Summer 2012 © Dr. Son Vuong
9
Ch 4: Network Layer and Routing
The IP Protocol
Routing
IP Format, Addressing, fragmentation,
Internet Control Protocols (ICMP)
RIP (Routing Information Protocol)
OSPF (Open Shortest Path First)
The Interior Gateway Routing Protocol
BGP – The Exterior Gateway Routing Protocol
IPv6
Internet Multicasting
Mobile IP
Cics 515 – Summer 2012 © Dr. Son Vuong
10
What have we covered?
IPv4, IPv6
What’s next ?
Internet Control Message Protocol (ICMP)
Address resolution (ARP)
Getting (dynamic) addresses (DHCP)
DNS
Routing protocols (RIP, OSPF, BGP)
Cics 515 – Summer 2012 © Dr. Son Vuong
11
University of British Columbia
CICS 515 (Part 2) Computer Networks
Lecture 5c – ICMP, ARP, DHCP, DNS
Instructor: Dr. Son T. Vuong
Email: [email protected]
The World Connected
Cics 515 – Summer 2012 © Dr. Son Vuong
12
Lect. 5c – Other IP protocols
ICMP, ARP, DHCP (Sect. 4.4.3, 5.4)
DNS (Sect. 2.5 )
Internet Control Message Protocol (ICMP) (Sect 4.4.3)
Address Resolution (ARP) (Sect 5.4)
Dynamic IP address assignment (DHCP) (Sect 5.4)
Domain Name System (DNS) (Sect2.5)
Cics 515 – Summer 2012 © Dr. Son Vuong
13
ICMP: Internet Control Message Protocol
RFC 792
Used by hosts & routers to communicate
network-level information
error
reporting: unreachable host, network, port,
protocol
echo request/reply (used by ping)
Network-layer “above” IP:
ICMP
msgs carried in IP datagrams
ICMP message: type (1B), code (1B),
checksum (2B) plus part of IP datagram
causing error (header + first 8 bytes of data)
Cics 515 – Summer 2012 © Dr. Son Vuong
14
ICMP datagram structure
ICMP msgs carried in IP datagrams
ICMP data contains part of IP datagram
causing error (IP header + first 8 bytes of data)
Cics 515 – Summer 2012 © Dr. Son Vuong
15
ICMP: Internet Control Message Protocol
Type
0
3
3
3
3
3
3
4
5
8
9
10
11
12
Code
0
0
1
2
3
6
7
0
0-3
0
0
0
0
0
description
echo reply (ping)
dest. network unreachable
dest host unreachable
dest protocol unreachable
dest port unreachable
dest network unknown
dest host unknown
source quench (congestion control - not used)
redirect a host to a better router
echo request (ping)
route advertisement
router discovery (solicitation)
TTL expired
bad IP header
Cics 515 – Summer 2012 © Dr. Son Vuong
16
“Real” Internet delays and routes
What do “real” Internet delay & loss look like?
traceroute (tracert) program: provides delay
measurement from source to router along endend Internet path towards destination. For all i:
sends three UDP packets that will reach router i on
path towards destination
router i will return packets to sender
sender times interval between transmission and
reply.
3 probes
3 probes
3 probes
Cics 515 – Summer 2012 © Dr. Son Vuong
17
Traceroute and ICMP
Source sends series of UDP
segments to dest
When ICMP message arrives,
source calculates RTT
First has TTL =1
Traceroute does this 3 times
Second has TTL=2, etc.
Stopping criterion
Unlikely port number
When nth datagram arrives to UDP segment eventually
arrives at destination host
nth router:
Router discards datagram Destination returns ICMP “port
unreachable” packet (type 3,
And sends to source an
code 3)
ICMP message (type 11,
When source gets this ICMP,
code 0)
stops.
Message includes name of
router& IP address
Cics 515 – Summer 2012 © Dr. Son Vuong
18
Address Resolution Protocol (ARP)
How do we convert the IP address of each node
(either the destination node, or a router) into the
address on the local network? E.g. IP -> Ethernet.
Each machine keeps a mapping of IP address to
physical addresses in a cache.
E.g. cascade.cs.ubc.ca 08:00:20:79:70:f5
dragon.cs.ubc.ca 08:00:09:27:b4:73
etc…
What if the mapping isn’t known, or has expired?
Send an ARP (Address Resolution Protocol)
broadcast message over the network.
Cics 515 – Summer 2012 © Dr. Son Vuong
19
ARP Packet Format
0
8
16
Hardware type = 1
HLen = 48
PLen = 32
31
ProtocolType = 0x0800
Operation
SourceHardwareAddr (bytes 0-3)
SourceHardwareAddr (bytes 4-5)
SourceProtocolAddr (bytes 2-3)
SourceProtocolAddr (bytes 0-1)
TargetHardwareAddr (bytes 0-1)
TargetHardwareAddr (bytes 2-5)
TargetProtocolAddr (bytes 0-3)
Cics 515 – Summer 2012 © Dr. Son Vuong
20
ARP Fields
Request format
HardwareType
- Type of physical network
(e.g., Ethernet)
ProtocolType - Type of higher layer protocol
(e.g., IP)
HLEN & PLEN - Length of physical and
protocol addresses (measured in bits)
Operation - Request for an address, or
response to a request.
Source/Target Physical/Protocol addresses
Cics 515 – Summer 2012 © Dr. Son Vuong
21
ARP Comments
An ARP packet sits at the same level in the
protocol graph as an IP packet. However ARP
service is used by IP; thus ARP can also be
viewed as a sublayer below IP.
ARP table entries timeout in about 10 minutes
Update the ARP table with information about
the source when you are the target. Hence,
both source/target physical/protocol addresses
are in the packet.
Cics 515 – Summer 2012 © Dr. Son Vuong
22
Dynamic Host Configuration Protocol
(DHCP)
How does a host get an IP address?
Fixed – assigned
Dynamic – changeable: via DHCP
why?
Cics 515 – Summer 2012 © Dr. Son Vuong
23
Dynamic Host Configuration Protocol
(DHCP)
DHCP allows config info (IP address etc)
stored in DHCP server to be retrieved
automatically by each host when booted or
connected to network (via broadcast
DHCPDiscover message)
that is, special IP address 255.255.255.255
ignored by everyone except the DHCP server
Cics 515 – Summer 2012 © Dr. Son Vuong
24
DHCP (cont’d)
DHCP also allows dynamic assignment of IP
addresses to hosts (DHCP server maintains a
pool of available IP addresses to lease to
host and host need to renew lease
periodically).
It is not desirable to have a DHCP server on
every network – instead, uses a relay agent
for each network.
Relay agent unicasts DHCP request to server
Cics 515 – Summer 2012 © Dr. Son Vuong
25
DHCP with relay agent
Unicast to server
DHCP
relay
Other networks
DHCP
server
Broadcast
Host
Cics 515 – Summer 2012 © Dr. Son Vuong
26
DHCP Packet Format
Operation
HType
HLen
Hops
Transaction ID (Xid)
No. of secs
Flags/unused
Client IP addr
Your IP addr (yiaddr)
Server IP addr
Gateway IP addr
Client hardware addr (chaddr) (16 bytes)
Server name (64 bytes)
file (128 bytes)
options
DHCP is derived from an earlier protocol called BOOTP
Cics 515 – Summer 2012 © Dr. Son Vuong
27
DHCP (cont’d)
Sent using UDP
Client puts hardware address in chaddr
Server replies with IP address in yiaddr (and
other config info, e.g. gateway addr, server IP
address, etc)
Types of DHCP packets (spec’d as options):
Discover, Offer, Request, Decline, Ack,
Nack, Release
Scalability/manageability -- recurring theme
(via relay/proxy)
Cics 515 – Summer 2012 © Dr. Son Vuong
28
DHCP Scenario
DHCP Client
DHCP Server
...
...
Cics 515 – Summer 2012 © Dr. Son Vuong
29
Layering Relationships between
ICMP, ARP, DHCP and IP, UDP
ICMP/IP
IP calls ARP/Link(Ethernet)
DHCP(BOOTP) / UDP(67/68) (for simple
configinfo)
DHCP(BOOTP) / TFTP/UDP(69) (to get config file)
Cics 515 – Summer 2012 © Dr. Son Vuong
30
DNS: Domain Name System
Cics 515 – Summer 2012 © Dr. Son Vuong
31
Chapter 2: Application layer
2.1 Principles of network applications
2.2 Web and HTTP
2.3 FTP
2.4 Electronic Mail
SMTP, POP3, IMAP
2.5 DNS
2.6 P2P file sharing
2.7 Socket programming with TCP
2.8 Socket programming with UDP
2.9 Building a Web server
Cics 515 – Summer 2012 © Dr. Son Vuong
32
Domain Name System (DNS)
Overview
What do names do?
identify
objects
help locate objects
define membership in a group
specify a role
convey knowledge of a secret
Name space
defines
set of possible names
consists of a set of name to value bindings
Cics 515 – Summer 2012 © Dr. Son Vuong
33
Properties
Names versus addresses
Location transparent versus locationdependent
Flat versus hierarchical
Global versus local
Absolute versus relative
By architecture versus by convention
Unique versus ambiguous
Cics 515 – Summer 2012 © Dr. Son Vuong
34
Examples
Hosts
cheltenham.cs.princeton.edu
192.12.69.17
80:23:A8:33:5B:9F
Files
/usr/llp/tmp/foo
192.12.69.17
(server, fileid)
Users
Larry Peterson
Cics 515 – Summer 2012 © Dr. Son Vuong
[email protected]
35
Summary of “Naming” or identification
Domain name: a name that makes sense to a
human -- e.g. “cascade.cs.ubc.ca”
IP address: an identifier that makes sense to
hosts and routers -- e.g. “142.103.7.7”
Physical address: an identifier that makes sense
to the interface card -- e.g. “8:0:2b:e4:b1:2”
Cics 515 – Summer 2012 © Dr. Son Vuong
36
DNS: Domain Name System
People: many identifiers:
SSN, name, passport #
Internet hosts, routers:
IP address (32 bit) used for addressing
datagrams
“name”, e.g.,
www.yahoo.com - used
by humans
Q: map between IP
addresses and name ?
Cics 515 – Summer 2012 © Dr. Son Vuong
Domain Name System:
distributed database
implemented in hierarchy of
many name servers
application-layer protocol
host, routers, name servers
to communicate to resolve
names (address/name
translation)
note: core Internet function,
implemented as applicationlayer protocol
complexity at network’s
“edge”
37
DNS: Domain Name System
DNS services
Hostname to IP address
translation
Host aliasing
Canonical and alias
names
Mail server aliasing
Load distribution
Why not centralize DNS?
single point of failure
traffic volume
distant centralized database
Maintenance
doesn’t scale!
Replicated Web servers:
set of IP addresses for
one canonical name
Cics 515 – Summer 2012 © Dr. Son Vuong
38
Examples (cont)
Mailboxes
User
2
vuong @ cs.ubc.ca
cs.ubc.ca
Name
server
1
Mail
program
142.103.7.51
142.103.7.51
4
3
TCP
142.103.7.51
5
IP
Services
nearby ps printer with short queue and 2MB
Cics 515 – Summer 2012 © Dr. Son Vuong
39
Domain Naming System
Hierarchy
edu
princeton … mit
cs
com
gov
cisco… yahoo nasa …nsf
mil
org
arpa …navy
acm …ieee
net
uk
fr
ee physics
ux01 ux04
Name
chinstrap.cs.princeton.edu
Cics 515 – Summer 2012 © Dr. Son Vuong
40
Distributed, Hierarchical Database
Root DNS Servers
com DNS servers
yahoo.com amazon.com
DNS servers DNS servers
org DNS servers
pbs.org
DNS servers
edu DNS servers
poly.edu
DNS servers
umass.edu
DNS servers
Client wants IP for www.amazon.com; 1st approx:
Client queries a root server to find com DNS server
Client queries com DNS server to get amazon.com DNS
server
Client queries amazon.com DNS server to get IP address
for www.amazon.com
Cics 515 – Summer 2012 © Dr. Son Vuong
41
Name Servers
Partition hierarchy into zones
Root name servers
Top Level Domain
(TLD) Servers
edu
princeton … mit
cs
ee
com
gov
cisco … yahoo nasa … nsf
mil
org
arpa … navy
acm … ieee
uk
fr
physics
ux01 ux04
net
Root
Each zone corresponds to an
admin authority (implemented by
two or more name servers for
redundancy)
Authoritative Servers
CS
name server
UBC
…
name server
name server
…
Cisco
name server
ECE
name server
Local Name Servers (LNS)
Cics 515 – Summer 2012 © Dr. Son Vuong
42
DNS: Root name servers
contacted by local name server that can not resolve name
root name server:
contacts authoritative name server if name mapping not known
gets mapping
returns mapping to local name server
a Verisign, Dulles, VA
c Cogent, Herndon, VA (also Los Angeles)
d U Maryland College Park, MD
k RIPE London (also Amsterdam, Frankfurt)
g US DoD Vienna, VA
h ARL Aberdeen, MD
i Autonomica, Stockholm (plus 3 other locations)
j Verisign, ( 11 locations)
e NASA Mt View, CA
f Internet Software C. Palo Alto, CA
m WIDE Tokyo
(and 17 other locations)
b USC-ISI Marina del Rey, CA
l ICANN Los Angeles, CA
Cics 515 – Summer 2012 © Dr. Son Vuong
13 root name
servers worldwide
43
TLD and Authoritative Servers
Top-level domain (TLD) servers: responsible for com,
org, net, edu, etc, and all top-level country domains uk,
fr, ca, jp.
Verisign controls .com and .net TLDs
Many companies act as intermediaries
Educause for edu TLD
Authoritative DNS servers: organization’s DNS servers,
providing authoritative hostname to IP mappings for
organization’s servers (e.g., Web and mail).
Can be maintained by organization or service provider
Cics 515 – Summer 2012 © Dr. Son Vuong
44
Local Name Server
Does not strictly belong to hierarchy
Each ISP (residential ISP, company,
university) has one.
Also
called “default name server”
When a host makes a DNS query, query is
sent to its local DNS server
Acts
as a proxy, forwards query into
hierarchy.
Cics 515 – Summer 2012 © Dr. Son Vuong
45
root DNS
server
Example: Iterative queries
2
Host at cis.poly.edu wants IP
address for gaia.cs.umass.edu
3
TLD DNS
server
4
5
iterative query:
contacted server
replies with name of
server to contact
“I don’t know this
name, but ask this
server”
local DNS server
dns.poly.edu
1
8
requesting host
cis.poly.edu
7
6
authoritative DNS server
dns.cs.umass.edu
gaia.cs.umass.edu
Cics 515 – Summer 2012 © Dr. Son Vuong
46
Recursive queries
root DNS
server
recursive query:
2
puts burden of name
7
resolution on
contacted name
server
local DNS server
heavy load?
dns.poly.edu
1
3
6
TLD DNS
server
5
4
8
requesting host
cis.poly.edu
authoritative DNS server
dns.cs.umass.edu
gaia.cs.umass.edu
Cics 515 – Summer 2012 © Dr. Son Vuong
47
DNS: caching and updating records
once (any) name server learns mapping, it caches
mapping
cache
entries timeout (disappear) after some time
TLD servers typically cached in local name servers
Thus
root name servers not often visited
update/notify mechanisms under design by IETF
RFC 2136
http://www.ietf.org/html.charters/dnsind-charter.html
Cics 515 – Summer 2012 © Dr. Son Vuong
48
DNS records
DNS: distributed db storing resource records (RR)
RR format: (name, value, type, ttl)
Type = A
name is hostname
value is IP address
Type = CNAME
Type = NS
name is domain (e.g.
foo.com)
value is IP address of
authoritative name
server for this domain
servereast.backup2.ibm.com
Cics 515 – Summer 2012 © Dr. Son Vuong
name is alias name for some
“cannonical” (the real) name
www.ibm.com is really
value is cannonical name
Type = MX
value is name of
mailserver associated with
name
49
Example: Root Server
(princeton.edu, cit.princeton.edu, NS, IN)
[in the Princeton domain]
(cit.princeton.edu, 128.196.128.233, A, IN)
(cisco.com, thumper.cisco.com, NS, IN)
[in the Cisco domain]
(thumper.cisco.com, 128.96.32.20, A, IN)
…
Cics 515 – Summer 2012 © Dr. Son Vuong
50
Further example: Princeton Server
[within Princeton domain]
(cs.princeton.edu, optima.cs.princeton.edu, NS, IN)
[name server]
(optima.cs.princeton.edu, 192.12.69.5, A, IN)
(ee.princeton.edu, helios.ee.princeton.edu, NS, IN)
[another name server]
(helios.ee.princeton.edu, 128.196.28.166, A, IN)
(jupiter.physics.princeton.edu, 128.196.4.1, A, IN)
(saturn.physics.princeton.edu, 128.196.4.2, A, IN)
(mars.physics.princeton.edu, 128.196.4.3, A, IN)
(venus.physics.princeton.edu, 128.196.4.4, A, IN)
Cics 515 – Summer 2012 © Dr. Son Vuong
51
Further example: CS Server
[within the CS domain in the
Princeton domain]
(cs.princeton.edu, optima.cs.princeton.edu, MX, IN)
[mail server]
(cheltenham.cs.princeton.edu, 192.12.69.60, A, IN)
(che.cs.princeton.edu, cheltenham.cs.princeton.edu,
CNAME, IN)
[alias/actual]
(optima.cs.princeton.edu, 192.12.69.5, A, IN)
(opt.cs.princeton.edu, optima.cs.princeton.edu,
CNAME, IN)
[another alias]
(baskerville.cs.princeton.edu, 192.12.69.35, A, IN)
(bas.cs.princeton.edu, baskerville.cs.princeton.edu,
CNAME, IN)
Cics 515 – Summer 2012 © Dr. Son Vuong
52
DNS protocol, messages
DNS protocol : query and reply messages, both with
same message format
msg header
identification: 16-bit id for
query, reply to query uses
same id
flags:
query or reply
recursion desired
recursion available
reply is authoritative
Cics 515 – Summer 2012 © Dr. Son Vuong
53
DNS protocol, messages
Name, type fields
for a query
RRs in reponse
to query
records for
authoritative servers
additional “helpful”
info that may be used
Cics 515 – Summer 2012 © Dr. Son Vuong
54
Inserting records into DNS
Example: just created startup “Network Utopia”
Register name networkuptopia.com at a registrar (e.g.,
Network Solutions)
Need to provide registrar with names and IP addresses of
your authoritative name server (primary and secondary)
Registrar inserts two RRs into the com TLD server:
(networkutopia.com, dns1.networkutopia.com, NS)
(dns1.networkutopia.com, 212.212.212.1, A)
Put in authoritative server Type A record for
www.networkuptopia.com and Type NS record for
networkutopia.com
How do people get the IP address of your Web site?
Cics 515 – Summer 2012 © Dr. Son Vuong
55
Dig www.telus.ca
;; QUESTION SECTION:
;www.telus.ca.
IN
A
;; ANSWER SECTION:
www.telus.ca.
86400 IN
CNAME www.telus.com.
www.telus.com.
600
IN
A
205.206.163.16
;; AUTHORITY SECTION:
telus.com.
600
IN
NS
dns1.cidc.telus.com.
telus.com.
600
IN
NS
dns2.cidc.telus.com.
;; ADDITIONAL SECTION:
dns1.cidc.telus.com. 59695 IN
A
216.123.224.131
dns2.cidc.telus.com. 59695 IN
A
66.203.199.203
DNS DDoS, Poisoning and Hijacking
Cics 515 – Summer 2012 © Dr. Son Vuong
56
Layering Relationships between
ICMP, ARP, DHCP, DNS and IP, UDP
ICMP/IP, ICMPv6/IPv6
IP calls ARP/Link(Ethernet)
DHCP(BOOTP) / UDP(68) (for simple configinfo)
DHCP(BOOTP) / TFTP/UDP(69) (to get config file)
DNS / UDP(53)
Cics 515 – Summer 2012 © Dr. Son Vuong
57
What have we covered?
IPv4, IPv6
Internet Control Message Protocol (ICMP)
Address resolution (ARP) and getting
(dynamic) addresses (DHCP)
What’s next ?
Routing protocols (RIP, OSPF, BGP)
Cics 515 – Summer 2012 © Dr. Son Vuong
58
IPv6
Initial motivation: 32-bit address space soon to
be completely allocated.
Additional motivation:
header
format helps speed processing/forwarding
header changes to facilitate QoS
IPv6 datagram format:
fixed-length 40 byte header
no fragmentation specified in basic header
Cics 515 – Summer 2012 © Dr. Son Vuong
59
IPv6 Header (Cont)
Priority: identify priority among datagrams in flow
Flow Label: identify datagrams in same “flow.”
(concept of“flow” not well defined).
Next header: identify upper layer protocol for data
Cics 515 – Summer 2012 © Dr. Son Vuong
60
Other Changes from IPv4
Checksum: removed entirely to reduce
processing time at each hop
Options: allowed, but outside of header,
indicated by “Next Header” field
ICMPv6: new version of ICMP
additional
message types, e.g. “Packet Too Big”
multicast group management functions
Cics 515 – Summer 2012 © Dr. Son Vuong
61
Transition From IPv4 To IPv6
Not all routers can be upgraded simultaneous
no
“flag days”
How will the network operate with mixed IPv4 and
IPv6 routers?
Tunneling: IPv6 carried as payload in IPv4
datagram among IPv4 routers
Cics 515 – Summer 2012 © Dr. Son Vuong
62
Dual
IPv6/IPv4
Router
Tunneling
Logical view:
Physical view:
Dual
IPv6/IPv4
Router
A
B
IPv6
IPv6
A
B
C
IPv6
IPv6
IPv4
Flow: X
Src: A
Dest: F
data
A-to-B:
IPv6
Cics 515 – Summer 2012 © Dr. Son Vuong
E
F
IPv6
IPv6
D
E
F
IPv4
IPv6
IPv6
tunnel
Src:B
Dest: E
Src:B
Dest: E
Flow: X
Src: A
Dest: F
Flow: X
Src: A
Dest: F
data
data
B-to-C:
IPv6 inside
IPv4
B-to-C:
IPv6 inside
IPv4
Flow: X
Src: A
Dest: F
data
E-to-F:
IPv6
63
Ch 4: Network Layer and Routing
The IP Protocol
Routing
IP Format, Addressing, fragmentation,
Internet Control Protocols (ICMP)
RIP (Routing Information Protocol)
OSPF (Open Shortest Path First)
The Interior Gateway Routing Protocol
BGP – The Exterior Gateway Routing Protocol
IPv6
Internet Multicasting
Mobile IP
Cics 515 – Summer 2012 © Dr. Son Vuong
64
What have we covered?
IPv4, IPv6
Internet Control Message Protocol (ICMP)
Address resolution (ARP) and getting
(dynamic) addresses (DHCP)
DNS
What’s next ?
Routing protocols (RIP, OSPF, BGP)
Cics 515 – Summer 2012 © Dr. Son Vuong
65