Ch 6 Flashcards
IPv6 traffic class field
1 bytes
replaces DS field
version field
4 bit value
IPv4 (0100) vs IPv6 (0110)
next hop address
IP of the next router to forward the packet for that network
2 Windows commands to show routing table
route print
netstat -r
packet sizes
IPv4 - 20 bytes
IPv6 - 40 bytes
IPv6 payload length field
16 bits (2 bytes) length of data payload of packet
3 Cisco router types
Branch (ISR G2) WAN (Catalyst switches, Aggregation Services Routers) Service Provider (Carrier Routing System and 7600 routers)
in-band vs out-of-band
in-band carry user traffic and require IP addressing
out-of-band dedicated to configure, manage, and troubleshoot, don’t carry user traffic
definition of routing
the process of sending packets to hosts on a remote network
IPv6 hop limit field
8 bit (2 bytes) replaces TTL field
next header
8 bits (2 bytes) same as IPv4 protocol field indicates data payload type
HWIC
high speed WAN interface card
Basic characteristics of a IP
Connectionless
Best effort delivery
Media independent
ICMP
Internet Control Message Protocol
IPv6 extension headers EH
provide optional network layer information
placed between IPv6 header and payload
used for fragmentation, security, mobility
definition of hop
each router that a packet crosses to reach its destination
IOS command for viewing routing table
show ip route
fragmentation definition
when an intermediate device splits up a packet to forward it over a medium with a smaller MTU
routers don’t fragment IPv6 packets
default route definition
a route that device uses to send a packet to a remote network when network doesn’t match any other routes.
TTL Time to Live
1 byte
limits the lifetime of packet
each hop TTL is decremented
if 0, router sends ICMP Time Exceeded message
improvements of IPv6
longer addresses (128 bits - 16 bytes) vs (32 bits - 4 bytes)
headers have fewer fields
NAT not needed
MTU maximum transmission unit
the maximum size of the PDU that a given medium can support
data link layer tells network layer its MTU
best effort definition
packet delivery is not guaranteed
cannot retransmit undelivered or corrupt packets
function of network layer
enable the transport of data from one network to another.