Category: Uncategorized

IS-IS packet types IS-IS calls PDU instead of packets. IS-IS Packet Encapsulation IS-IS packets are encapsulated directly into data link layer, or layer 2, headers. that is: MAC header + ISIS Header + ISIS Data. When an intermediate system wants to transmit data in a packet, it prepends an IS-IS header to the front of…

Fundamentally, python is a interpreter language which is unlike c or c++ which is compiled as well. Compiler job is to take the high level code and then convert into bytecode which can be executed by the OS So, what does interpreter do? interpreter takes some code and translates on the fly and execute on…

https://www.youtube.com/watch?v=DtGrdB8wQ_8

Network automation is a very hard problem. It is a distributed, parallel, real-time, highly available, performance-sensitive, security-sensitive control problem at the heart of society. This requires a system architecture. Design: requirements: the term SDN evolved to mean a variety of things: network virtualization in the cloud, dynamic service chains for service provider subscribers, dynamic traffic…

VxLAN: Use Layer 3 transport to carry layer 2 data. Any servers connected on different broadcast domain can talk to each other as if they are on same link.VXLAN is a MAC-in-IP/UDP encapsulation type, adding a total of 50 bytes to the original packet post-encapsulation. This is not just a single header, but multiple headers…

Multicast:One copy of the packet will send to the receivers who are “interested”. https://www.youtube.com/watch?v=BC8MfzMSRhY&list=PLVND-cRwt9SNw9_EIK4GGDBAT0wtz0xSC&index=5 Layer 3 multicast: reservation: CIDR details 224.0.0.0/24 for Routing protocols. link local scope. TTL 1 or 2 232.0.0.0/8 For multicast stream for which source is known 239.0.0.0/8 similar as RFC1918. within a ASN Layer 2 multicast: We use mapping from the…

Type 1: Positional arguments person(“peth”,25) Type 2: Keyword arguments person(name=”peth”, age=25) Type 3: Default Type 4: Variable length Type 5: Keyworded Variable Length Arguments

iBGP rule: A router adds its AS number to a route’s AS_PATH only when the route is sent to an EBGP neighbor. The AS number is not added to routes sent to an IBGP neighbor. Why we need full-mesh in iBGP: If we have RTR1–>RTR2–>RTR3 and iBGP peering is between RTR1 and RTR3 logically, the control plane…

SNMP: https://www.youtube.com/watch?v=HXu0Ifj0oWU SNMP components: SNMP Versions: SNMP message types: gMNI https://www.youtube.com/watch?v=psj4KeCWuOc

At a very high level, the operation of OSPF is easily explained: Hello packets are exchanged between neighbors as keepalives, and LSAs are retransmitted every 30 minutes. If the network topology is stable, no other activity should occur. Whenever a router sends a Hello, it includes in the packet the Router IDs of all neighbors…