Phase 3 Master Exam Bank: Cisco CLI Syntax & OSI Reference Models

A 7-layer theoretical architectural framework standardizing network communication functions.

7 layers.

7: Application, 6: Presentation, 5: Session, 4: Transport, 3: Network, 2: Data Link, 1: Physical.

4: Application, 3: Transport, 2: Internet, 1: Network Access.

The formatted data block passed across layer boundaries during network transmission.

Segment (TCP) / Datagram (UDP).

Packet.

Frame.

Bits.

End-to-end communication, port process multiplexing, flow control, and error recovery.

Logical IP addressing, packet routing across intermediate networks, and path selection.

Physical MAC addressing, framing, and media access control across local LAN segment.

Transmitting raw bit streams over physical copper wire, optical fiber, or wireless RF.

Port 80.

Port 443.

Port 22.

Port 53.

TCP is connection-oriented and reliable (guaranteed delivery); UDP is connectionless and lightweight (fast, no retries).

SYN, SYN-ACK, ACK.

A switch port carrying traffic for a single untagged VLAN to end-user devices.

A switch port carrying traffic for multiple tagged VLANs between switches or routers.

Frame tagging protocol that inserts a 4-byte header containing a 12-bit VLAN ID into Ethernet frames.

Untagged VLAN on an 802.1Q trunk link (default VLAN 1).

Switch>

Switch#

Switch(config)#

enable

configure terminal

hostname Switch-1

vlan 10

switchport access vlan 10

switchport mode trunk

copy running-config startup-config (or write memory)

show mac address-table

Data -> Add Transport header (Segment) -> Add IP header (Packet) -> Add MAC header & FCS (Frame) -> Encode as electrical/optical signals (Bits).

Receive Bits -> Strip MAC header & verify FCS (Frame) -> Strip IP header (Packet) -> Strip Transport header (Segment) -> Deliver Data payload to Application.

20 bytes.

8 bytes.

Dynamic receiver window size adjustment indicating how many bytes sender can transmit before requiring ACK.

Sender sends FIN -> Receiver ACKs -> Receiver sends FIN -> Sender ACKs.

Full CLI script for Switch-A, Switch-B (vlan 10, vlan 20, switchport mode trunk), and Router-1 (interface Gi0/0.10 encapsulation dot1Q 10 ip address 192.168.10.1 255.255.255.0).

Inspects Source MAC on ingress, updates port table with 300s aging timer. Floods unknown Destination MAC frames to all active ports except ingress.

interface Gi0/0.10 -> encapsulation dot1Q 10 -> ip address 192.168.10.1 255.255.255.0.

interface vlan 10 -> ip address 192.168.10.1 255.255.255.0 -> no shutdown -> ip routing.

Blocking -> Listening -> Learning -> Forwarding (Prevents Layer 2 switching loops).

Bytes 0-5: Dest MAC; Bytes 6-11: Source MAC; Bytes 12-13: EtherType (0x0800 IPv4); Byte 14+: IP Header.

Switch with lowest Bridge ID (Priority + MAC address) becomes Root Bridge.

Access, Trunk, Dynamic Auto, Dynamic Desirable.

interface range Fa0/1 - 2 -> channel-group 1 mode active -> interface port-channel 1 switchport mode trunk.

router ospf 1 -> network 192.168.10.0 0.0.0.255 area 0.

Worked Cisco CLI script and protocol breakdown for scenario 11 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 12 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 13 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 14 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 15 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 16 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 17 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 18 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 19 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 20 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 21 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 22 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 23 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 24 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 25 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 26 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 27 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 28 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 29 covering VLAN trunking, static routing, and switch security configuration.

Worked Cisco CLI script and protocol breakdown for scenario 30 covering VLAN trunking, static routing, and switch security configuration.