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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…

CAM Table Vs FIB table: CAM table contains MAC address, egress port and vlan. Whereas, FIB table contains IP address, next-hop IP address, next-hop MAC address, Egress port. We use FIB and CAM Table in conjuction in multi-layer hardware based switching. Hardware based switching is always fast. Exceptions: Packets like ARP, IP packets which needs…

Single mode Vs multi-mode fiber: Single-Mode Fiber (SMF): Multi-Mode Fiber (MMF): QSFP28 LR4 QSFP28 SR4 hot-pluggable hot-pluggable SM fiber(upto 10KM) Multi-mode fiber(100 Meters) WDM tech: 4 lanes. each lanes has different Wavelength parrallel optics tech(4 lanes. each lanes transmit 25G) Choose single-mode fiber for long-distance communication and multi-mode fiber for short-distance, high-bandwidth connections within data…