Topic 7 Flashcards
What are the four basic functions performed by the network layer?
- Addressing end devices
- Encapsulation
- Routing
- De-encapsulation
These functions are essential for the operation of the network layer in the OSI model.
What does the Time-to-Live (TTL) field in the IPv4 header represent?
Layer 3 hop count. When it becomes zero the router will discard the packet.
TTL is used to prevent packets from circulating indefinitely in the network.
What are the three major limitations of IPv4?
- IPv4 address depletion
- Lack of end-to-end connectivity
- Increased network complexity
These limitations have led to the development of IPv6.
What are three improvements that IPv6 provides?
- Increased address space
- Improved packet handling
- Eliminates the need for NAT
IPv6 uses a 128-bit address format, allowing for vastly more unique addresses.
What is a characteristic of IP regarding connection establishment?
Connectionless
IP does not establish a connection before sending packets.
What does ‘Best Effort’ mean in the context of IP?
Does not guarantee packet delivery.
This characteristic reduces overhead and relies on other protocols for delivery confirmation.
What does it mean for IP to be Media Independent?
IP does not concern itself with the type of frame required at the data link layer or the media type at the physical layer.
IP can operate over various media types, including copper, fiber, or wireless.
What is the purpose of the Differentiated Services and Traffic Class fields in the IP header?
Both are used for QoS.
They help manage the quality of service for different types of network traffic.
What are the three types of DESTINATION that a host can send packets to?
- Itself (127.0.0.1 for IPv4, ::1 for IPv6)
- Local Hosts
- Remote Hosts
These destinations determine how packets are routed in a network.
How does a source host determine whether an IPv4 destination is local or remote?
Local traffic is sent to the intermediary device; remote traffic is forwarded to the default gateway on the LAN.
This distinction is crucial for efficient packet routing.
What are the three main characteristics of a default gateway?
- Must have an IP address in the same range as the rest of the LAN
- Can accept data from the LAN and forward traffic off of the LAN
- Can route to other networks
A default gateway enables communication between different networks.
What happens if a device has no default gateway or a bad default gateway?
Its traffic will not be able to leave the LAN.
This can severely limit network functionality.
What are the three types of routes in a router’s routing table?
- Directly Connected
- Remote
- Default Route
These types of routes help the router determine where to forward packets.
List three characteristics of static routing.
- Must be configured manually
- Must be adjusted manually by the administrator when there is a change in topology
- Good for small non-redundant networks
Static routing is a straightforward but inflexible routing method.
List four characteristics of dynamic routing.
- Discover remote networks
- Maintain up-to-date information
- Choose the best path to the destination
- Find new best paths when there is a topology change
Dynamic routing adapts to changes in the network automatically.
What is the purpose of the no shutdown command?
Activates the interface.
This command is essential for enabling interfaces on routers and switches.
What does the show ip interface brief command do?
Verifies interface configuration or views status of all interfaces.
This command provides a quick overview of the operational status of interfaces.
Why must a switch have a default gateway address configured?
To remotely manage the switch from another network.
Without a default gateway, management of the switch from outside its local network is impossible.
