Network Devices

Cisco Devices
Modes:
> User (basic access)
# Priviledged (run show commands)
(config)# (config changes)
S1> enable
S1# configure terminal
S1(config)# vlan 10
S1(config-vlan)# name SALES
S1(config-vlan)# exit
S1(config)# end
S1#
S1# show vlan
R1# show run
S1# show ip interface brief
S1# show interfaces
Device configuration such as hostname is stored in running config
To save, "copy running-config startup-config"
ICMP PDU (Ping Simulation)
PC (Office Admin) > SW (Office SW1) > Printer0
1. Last: (Blank), At: Office-Admin (ICMP)
Outbound:
Layer 3:
ICMP echo request 
Source IP = unspecified, device sets to port's IP
Destination IP in same subnet, device sets next hop to destination IP
Layer 2:
Next hop = unicast, looks it up in ARP table
Found in ARP, ARP process sets frame destination accordingly
Layer 1:
FastEthernet0 sends the Frame
2. Last: Office-Admin, At: Office-SW1 (ICMP)
Inbound:
Layer 1:
Receives Frame
Layer 2:
Frame source MAC address not in MAC table, adds it
(Unicast Frame) look up Destination MAC address in MAC table
Outbound:
Layer 2:
Not in table, Floods frame to all ports in VLAN except inbound
Layer 1:
Ports 1, 2, 3, 4, 5, 6 send Frame
3. Last: Office-SW1, At: Office-R1 (ICMP)
Inbound:
Layer 1:
Receives Frame on G0/0/0
Layer 2:
Subinterface G0/0/0.20 accepts from this VLAN
Frame destination MAC does not match receiving port's MAC
Drops the Frame
4. Last: Office-SW1, At: Printer0 (ICMP)
Inbund:
Layer 1:
Receives Frame on FE0
Layer 2:
Frame Destination MAC = receiving port's MAC
De-capsulate PDU from the Frame
Layer 3:
Packet Destination IP = Device Destination IP
De-capsulate Packet, identifies ICMP, processes it
Identifies as Echo request message
Outbound:
Layer 3:
ICMP process sends Echo reply
Destination IP = same subnet, sets next hop to Destination IP
Layer 2:
Next hop = unicast, looks it up in ARP table
Found in ARP, ARP sets Frame desination MAC to the same
Encapsulates PDU into Frame
Layer 1:
FE0 sends Frame
5. Last: Printer0, At: Office-SW1 (ICMP)
Inbound:
Layer 1:
GE1/0/17 Receives Frame
Layer 2:
Frame source MAC is not in MAC table, adds it
Unicast Frame, looks up destination MAC in table
Outbound:
Layer 2:
Outgoing port = access port
Switch sends the frame out of that port
Layer 1:
GE1/0/19 sends the Frame
6. Last: Office-SW1, At: Office-Admin (ICMP)
Inbound: 
Layer 1: FE0 Receives Frame
Layer 2:
Frame destination MAC = Receiving port MAC
Decapsulates Frame
Layer 3:
Packet destination IP = device IP
decapsulates Packet
Identifies ICMP Packet
ICMP process received Echo reply message