Routing
Routing is a process that takes place at the Network Layer (Layer 3) of the OSI model. It is the process by which a router will decide out of which interface it will send a packet based on its destination address.
When a router receives a packet, it will examine the destination IP address and compare it with the entries it has in the Routing Table. Based on those entries, it will forward the packet out of the appropriate egress interface.
Routing is a fundamental operation of the IPv4 and IPv6 protocols and enables end to end (host to host) communication.
Links:
https://forum.networklessons.com/t/subnetting-in-decimal-fast-way/1209/44?u=lagapidis
https://networklessons.com/cisco/ccna-200-301/introduction-to-routers-and-routing
Links to this page:
- home
- AAA - RADIUS vs TACACS+
- ACL - Applying in a VRF environment
- ARP - Static ARP entry for own IP address
- Anycast
- BFD - Control Plane Independent (CPI) bit
- BFD - with multiple routing protocols
- BFD how an administrative change differs from a failure
- BGP - Autonomous System (AS)
- BGP - Autonomous System Number
- BGP - Discontiguous Autonomous Systems
- BGP - FSM - Active state
- BGP - FSM - Connect State
- BGP - Finite State Machine (FSM)
- BGP - IGP-BGP redistribution best practices
- BGP - Labeled Unicast
- BGP - Loop Prevention
- BGP - Network Layer Reachability Information (NLRI)
- BGP - TCP Peering Session Process
- BGP - The BGP Table
- BGP - The BGP table vs the Routing table
- BGP - Why is MED non-transitive
- BGP - aggregate-address command in action
- BGP - iBGP split horizon rule
- BGP - multicast routing
- BGP - network vs redistribute commands
- BGP - oldest path attribute
- BGP - redistributing iBGP routes into an IGP
- BGP 4-Byte AS Number - Asdot notation
- BGP 4-Byte AS Number - Asdot plus notation
- BGP 4-Byte AS Number - Asplain notation
- BGP AS Override feature
- BGP Allow-AS in
- BGP Asymmetric routing when using ASA with AWS
- BGP Confederation peerings
- BGP Load balancing
- BGP Originator ID
- BGP RIB failure
- BGP Update Groups
- BGP advertising a default route
- BGP communities
- BGP community types
- BGP installing a BGP-learned route into the routing table
- BGP paths indicated in the show ip bgp command
- BGP peering redundancy using loopbacks
- BGP soft reconfiguration on Cisco ASA
- BGP soft reconfiguration
- BGP using next-hop-self with a route reflector
- BGP why do we need an IGP for BGP to work
- BGP
- Best practice - prevent connectivity loss of remote device
- Bidirectional Forwarding Detection (BFD)
- Career study advice
- Cisco Pagent Router
- Cisco Quantum Flow Processor
- CoPP - Best practices and operation
- Configuration Register
- DHCP - Cisco Client ID format
- DHCP relay agent
- DHCPv6 relay agent
- DMVPN - IPsec encryption order of operations
- DMVPN - NHRP purge request
- DMVPN - Phase 2 and multicast traffic
- DMVPN - Phase 2 and summarization
- DMVPN - What is the best routing protocol to use
- DMVPN - spoke redundancy
- DMVPN dual hub single cloud
- DMVPN
- EGP
- EIGRP - Router ID and loop prevention
- EIGRP LFA FRR
- EIGRP redistributing named mode
- EIGRP unequal cost load balancing
- EIGRP what happens when a feasible successor fails
- EIGRP
- Equal-cost Multi-path routing
- Ethernet - speed and duplex mismatches
- FHRP Communication Between Redundant Routers
- FlexVPN Hub and Spoke backup routes
- GRE - Recursive routing error
- Hardware - Application Specific Integrated Circuit (ASIC)
- Hardware - Layer-3-aware ASIC and IGMP snooping
- ICMP - response to a ping that is blocked by an ACL
- IETF
- IGMP - fast leave
- IGMP default IOS configurations
- IOS - ip http server
- IP - When is the TTL decremented in a router
- IP Addressing on a Router
- IP Routing table - process by which entries are matched
- IP routing table - 'L' and 'C' entries
- IP routing table - default route
- IPv4 - ToS Byte definition
- IPv4 - no subnet mask information in the IP header
- IPv4 - subnet mask
- IPv4 point to point addresses
- IPv6 - RA suppression command
- IPv6 - understanding how to enable IPv6 functionality and routing on an IOS device
- IPv6 link-local address
- IS-IS - DIS and Pseudonode
- ISIS circuit-type command
- ISPs, tiers, transiting, and the Internet
- Interface - show interfaces counters explained
- Interface speed and bandwidth
- LFA - Topology Independent LFA
- LISP - map request and reply process
- LISP - what is it
- LISP
- Loop-Free Alternate (LFA) Fast Reroute (FRR)
- Loop-Free Alternate (LFA) and remote LFA
- Loops in layers 2 and 3
- MPLS - BGP customer prefixes do not appear in the LFIB
- MPLS - LDP source interface
- MPLS - Layer 2 VPNs
- MPLS - Segment Routing over MPLS
- MPLS - Using the BGP Allow-AS in feature
- MPLS - VPN label
- MPLS - multiarea OSPF in the core
- MPLS Customer Edge Router
- MPLS Label Edge Router
- MPLS advertising multiple customer subnets
- MPLS-TE - why are IGPs necessary
- MPLS
- Multicast - Example Use Cases
- Multicast - HSRP-aware PIM
- Multicast - MSDP
- Multicast - PIM Control Messages
- Multicast - PIM Snooping
- Multicast - PIM dense vs sparse mode
- Multicast - PIM
- Multicast - Understanding global vs interface-level configuration
- Multicast - reading the multicast routing table
- Multicast SPT and RPT
- NAT - Translation Table
- NAT - Twice NAT
- NAT - add-route keyword
- NAT - translate address not directly connected to edge device
- NAT port forwarding - specifying outside IP address
- NHRP
- NetFlow
- Network - Example of communication, encapsulation, and decapsulation, between hosts
- Network - Flapping
- Network - Layer 2 network
- Network - Layer 3 network
- Network - Transient traffic
- Network - broadcast domain
- Network - control plane
- Network - data plane
- Network Design - Load Balancing vs Load Sharing
- Network Design - Spine and leaf architecture
- Network Design - Traffic Engineering
- Network Time Protocol (NTP)
- Network planes
- Networking - Understanding Chassis devices
- Networks - Overlay Network
- Networks - Overlay Transport Virtualization (OTV)
- Networks - Underlay Network
- Next Generation Multicast Virtual Private Network (NG-MVPN)
- OSPF - Adjacencies in a Multi-Access network segment
- OSPF - Area Border Router (ABR)
- OSPF - Autonomous System Boundary Router (ASBR)
- OSPF - Link State Updates (LSUs)
- OSPF - OSPFv3 authentication
- OSPF - control plane vs data plane loops
- OSPF ABR and Loop Prevention
- OSPF Design - When to create new instance
- OSPF Discontiguous Area 0
- OSPF IS-IS comparison
- OSPF Type 4 LSA
- OSPF Why it is not suitable for use on the Internet
- OSPF extent of reconvergence process
- OSPF loop prevention
- OSPF network types
- OSPF point to point network type for Ethernet
- OSPF router ID
- OSPF why is a backbone area 0 necessary
- PBR - Transport Layer port number
- PBR next hop recursive
- PBR next hop verify availability
- Passive interface
- Ping - common reasons for failure
- Policy Based Routing acts on incoming traffic
- Protocol Independent Multicast (PIM)
- QoS - CBWFQ
- QoS - Classification by IP
- QoS - Tail Drop
- QoS - auto qos trust
- QoS - effects of bandwidth interface command
- QoS max-reserved-bandwidth
- RIP timers
- RIP
- Routers - what is a loopback interface
- Routing - A Directed Broadcast is only detected by the last router
- Routing - CEF adjacency fixup error
- Routing - Cisco Performance Routing (PfR)
- Routing - Classless and Classful routing protocols
- Routing - Distance-vector routing protocol use cases
- Routing - Dynamic routing protocols
- Routing - IP event dampening
- Routing - Injecting a Static Route
- Routing - Link-State vs Distance-Vector routing protocols
- Routing - Link-state routing protocol use cases
- Routing - The Null0 Interface
- Routing - default gateway
- Routing - default routing using DHCP
- Routing - directed broadcast
- Routing - ip default-network command
- Routing - link-local IPv6 next hop address needs exit interface
- Routing - redistribute command
- Routing - route tagging
- Routing - seed metrics
- Routing - what is a WAN port
- Routing - what is recursive routing
- Routing - what is redistribution
- Routing NX-OS passive-interface default
- Routing Table
- Routing in both directions
- SD-WAN - Unique Site IDs for vEdges
- SG300-10 - InterVLAN routing defaults
- SNMP monitoring routing on a Nexus device
- STP - Shortest Path Bridging (SPB)
- Segment Routing
- Split-horizon
- Summarization
- Switch configuring a routed port
- Switch protected port
- Switching - CEF Adjacency Table
- Switching - backplane
- Switching - switch fabric
- Switching
- Switchport - show vlan internal usage
- Telnet
- Traceroute
- Troubleshooting a slow network
- Unicast Reverse Path Forwarding (uRPF)
- VLAN - Private VLAN
- VLANs SVI
- VPN - Interesting Traffic
- VPN - default gateway for site to site VPN
- VPN - split tunneling
- VRF use cases
- VRF
- VRRP - Virtual IP doesn't respond to pings
- VRRP - using the same ID on different interfaces
- Wireless - FlexConnect Mode