Juniper JN0-280 Exam With Confidence Using Practice Dumps

Filter-Based Forwarding (FBF) in Junos OS allows traffic to be routed based on specific criteria such as source address, rather than just the destination address. This is useful in scenarios like policy routing or providing multiple paths for different types of traffic.

Step-by-Step Breakdown:

Instance-Type Forwarding:You must create aninstance-type forwardingrouting instance. This routing instance allows for different routing tables based on the incoming packet filter.

Command:

set routing-instances FBF-instance instance-type forwarding

Match Filter:You need to create afilterto match the traffic that will be forwarded according to your custom routing policy. This filter is applied to an interface to determine which traffic will use the custom forwarding instance.

Command Example:

set firewall family inet filter FBF-filter term 1 from source-address

In OSPF, routers exchange link-state information in different stages to establish full adjacency. TheMTU sizeis checked during theExchangestate.

Step-by-Step Breakdown:

OSPF Adjacency Process:

OSPF routers go through multiple stages when forming an adjacency:Down,Init,2-Way,ExStart,Exchange,Loading, andFull.

Exchange State:

During theExchangestate, OSPF routers exchangeDatabase Description (DBD)packets to describe their link-state databases. TheMTU sizeis checked at this stage to ensure both routers can successfully exchange these packets without fragmentation.

If there is anMTU mismatch, the routers may fail to proceed past the Exchange state.

Juniper Reference:

MTU Checking in OSPF: Junos uses the Exchange state to check for MTU mismatches, ensuring that routers can properly exchange database information without packet fragmentation issues.

Per-flow load balancingensures that packets within the same flow are always forwarded over the same path, ensuring that packet order is preserved.

Step-by-Step Breakdown:

Flow Definition:A flow is typically defined by a combination of packet attributes like source/destination IP, source/destination port, and protocol type. Packets that belong to the same flow are routed over the same path to avoid reordering.

Per-Flow Behavior:Inper-flow load balancing, the hashing algorithm ensures that all packets in a particular flow use thesame egress port, maintaining order across the network.

Juniper Reference:

Load Balancing in Juniper: This method ensures that flows are balanced across multiple paths while preventing packet reordering within a single flow.