- Four Processes
- 1. Addressing End Devices
- IP Addresses, must be unique. (Within network)
- 2. Encapsulation
- Receives a PDU from the transport layer, adds the IP information for destination and source. At this point the PDU is now called a packet.
- 3. Routing
- Directs packets to destinations on remote networks. (LANs use Switching)
- 4. Decapsulation
- Checks the IP header- if it is the destination, the IP header is removed and the PDU is sent to the transport layer.
- Network Layer Protocols
- 4.2 Billion
- 340 undecillion
- Connectionless: No link with remote site before sending.
- Unreliable; called ‘best effort’
- Media Independent
- Developed in 1983 by arpnet.
- IPv4 Header
- IPv4 value 0100
- Differential Services
- Determines Priority
- TTL (Time to Live)
- Limits life of a packet.
- Protocol - Data Payload Type
- Used to send error messages / control messages.
- Source IP
- Destination IP
- ID - Router might have to split the packet when transferring
- Flags between types.
- Fragment Offset
- Running out of IPv4 Addresses.
- Routing tables get too large.
- Lack of end to end connectivity.
- Increased address space. (128bits vs 320bits)
- Improved packet handling. (fewer header fields)
- Eliminates the need for NAT.
- Integrated security.
- Version (IPv6 = 0110)
- Traffic Clas
Author's Note: This is a screenshot from our school PC's cmd.
It won't be the same if you try to replicate the same command from your PC.
- Flow Label
- Real time apps
- Payload Length
- Next Header
- IPv4 Protocol Field
- Hop Limit
- Same as TTL
- Source Address
- Destination Address
25: Local Default Route
281: Local Network Addr
Same as ^: Limited Broadcast IP Address
local link network addr
global unicast ip addr
ipv6 reserved multicast addr
Things to learn from ‘show ip route’;
D - Learned
C - Connected
L - Local
S - Static
O - OSPF
A B C
C | 192.168.10.0/24 is directly connected, GigabitEthernet0/0
L | 192.168.10.1/32 is directly connected, GigabitEthernet0/0
A B C D E G
D | 10.1.1.0/24 [90/2170112] via 188.8.131.52, 00:00:05, Serial0/0/0
A: Identifies how the network was learned by the router.
B: Identifies the destination network and how it’s connected.
C: Identifies the interface on the router. (Administrative distance)
D: Identifies the metric to reach the remote network. (Smaller the number, better the route)
E: Identifies the next IP hop address to reach the remote network.
F: Identifies the amount of elapsed time since network was discovered.
G: Identifies the outgoing interface on the router to reach the destination network.
- Interfaces it has / kinds
- Non-volatile config memory
- How much flash it has
- ROM Info
- OS info
Router Configuration Steps
> enable Shortened: en
# config t Shortened: config t
# hostname R1 Shortened: #ho R1
# enable secret class
# line console 0
L# password cisco
# line vty 0 4 (Telnet/SSH)
# password cisco
# service password-encryption
# copy running-config startup-config Shortened: wr / copy run start
# banner motd #
Configuring LAN Interfaces (Gigabit / Ethernet)
# config t
# int G0/0
if# ip address 192.168.1.1 255.255.255.0
if# description Link to LAN-10
if# no shutdown
# int g0/1
if# ip add 192.168.11.1 255.255.255.0
if# no shut
Verify Interface Configuration
#show ip interface brief
- Status should be up.
- Administratively down means they haven’t been ‘no shutdown’
- Port should be up.
Default Gateways on a Host
- If you’re pinging a local host (does not pass through a RT) you don’t need a gateway, otherwise you do.
honey came in and she caught me red handed creeping with the girl next door;
Picture this we were both naked bangin on the bathroom floor.
How could I forget that I had given her the extra hey.
All this time she was standing there she never took her eyes off me.
Review Questions A
What IPV4 header field defines packet priority?
- Differentiated Services
Why do we not need IPV6?
- There are enough addresses for all devices.
What is the router boot sequence?
- Preform POST
- Load Bootstrap
- Find/Get IOS
- Locate Startup Config & Load
What prompt was the command entered at?
- Interface FastEthernet 0/0
- copy running-config startup-config
- No Shutdown
What are the two commands in windows to display the routing table?
- netstat -r
- route print
You are working on a router after making several changes w/o saving the power is lost. What 3 types of info is lost?
- Running Configuration
- IP Routing Table
- ARP Table
What are the 2 types of interfaces that allow access via the vty lines?
What command saves the current config so the system will use it on next boot?
- WR or copy running-config startup-config
For a manual pc network configuration, what 4 pieces of information have to be entered?
- IP Address
- Subnet Mask
- Default Gateway
- DNS Server