CCIE EI v1.1 - Layer 3 Technologies

Explore PIM dense mode, its push model, grafts and prunes, and how dense mode uses SPT to deliver multicast across a network.

Explore PIM sparse mode, its rendezvous point, and the pull model that avoids flooding; learn how IGMP joins, PIM register, and the shared and shortest path trees enable multicast delivery.

Explore rpf failure in multicast, demystifying dense and sparse modes with pim and igmp, and practice troubleshooting with per-packet rpf checks and lab scenarios.

Learn how dense mode uses state refresh to maintain the pruned state, sending prune and join messages and periodic control messages to speed joins and refresh the shortest path tree.

Learn PIM AutoRP, Cisco’s proprietary method for dynamically mapping rendezvous points in sparse mode, using ARP announce and mapping messages with a mapping agent and Auto ARP listener.

Explore how the PIM bootstrap router (BSR) uses an open standard to elect a rendezvous point and encapsulate BSR messages in the PIM v2 hello, simplifying multicast deployment.

Discover bidirectional PIM for many-to-many multicast, using shared trees and a rendezvous point, with designated forwarders and no S,G state or RPF checks.

Learn to configure PIM v6 multicast routing in IPv6 using sparse mode, set up a rendezvous point with BSR, join groups via MLD, and verify adjacencies and routes.

Explore how VRF Lite virtualizes routing tables per network, enabling isolation of subnets via route distinguishers and route targets, and using BGP to control inter-VRF routing.

Demonstrate policy based routing with route maps and extended ACLs to divert VLAN guest wifi traffic to a backup circuit, preserving the core switch default route.

Configure rip basic across two routers using version 1 and 2 with unicast only, activate networks via a network statement, and manage timers, triggered updates, and no auto summary.

Configure ripng for ipv6 by enabling the named process globally and on the interface, assign ipv6 addresses, enable ipv6 unicast routing, and redistribute connected routes for a basic ripng setup.

Explore how RIPv2 triggered updates replace periodic full updates with changes-only updates, including route poisoning using a maximum metric of 16 to advertise unreachable routes.

Discover rip v2 timers—update, invalid, hold down, and flush—and how they control updates, invalidation, and route garbage collection, with global and per-neighbor timer settings.

Learn how administrative distance governs route selection between RIP version 2 and OSPF, and how to tweak it with the distance command or access lists to influence redistribution scenarios.

Learn how to adjust RIPng administrative distance on a router using the distance command, overwrite earlier values, and verify IPv6 reachability to ensure correct route selection.

Explore how RIPv2 offset lists adjust metrics to influence path preference and filter routes, using inbound and outbound ACLs to favor a specific link to a network.

Learn how to use RIP version 2 distribute lists to filter routes with access lists, prefix lists, and gateway options, including wildcard masks, subnets, and multipath considerations.

Learn how to filter IPv6 routes in RIPng with distribute lists and prefix lists, using deny and a permit all rest (colon colon slash zero) for inbound and outbound prefixes.

Configure a conditional default route in RIP v2 using a prefix-list and route-map to advertise a gateway of last resort only when a specific connected prefix exists.

Learn how to originate a default IPv6 route in RIPng using a per-interface command with default information originate and a metric of five to advertise a default path.

Configure RIP version 2 summarization to control routing updates with automatic and manual summaries, using a ten slash eight summary and interface commands.

Configure RIPng summarization on the IPv6 interface by applying a summary address like 2000::/10 to advertise aggregated routes. Practice subnetting to determine effective summary ranges.

Configure RIP version 2 inside a VRF, with IPv4 VRF forwarding, using route distinguishers, redistributing interfaces, and maintaining secure, isolated routing across VRFs.

Master ripng vrf configuration to isolate routes across interfaces by upgrading cli with multi mode, enabling vf mode, and redistributing connected routes inside the vrf.

Learn how RIP version 2 authentication uses plain text or MD5 with a keychain that holds the password, including rotating keys and accept and send lifetimes.

Master redistributing routes between OSPF and RIP version 2, using manual metrics, route maps, and redistribute connected, with mutual redistribution and subnet awareness to avoid routing loops.

Learn packet types in layer 3 technologies, including hello, update, and ack packets, and explore 32-bit headers with version, opcode, checksum, sequence number, and autonomous system number to form adjacencies.

Differentiate internal and external routes, compare administrative distances (90 internal, 170 external), and examine TLVs that define metrics such as delay, bandwidth, hop count, reliability, load, and next hop.

Configure unicast or multicast neighbor adjacencies with the neighbor command and exit interface; enable ARP with network, multicast uses hello packets to 224.0.0. ten, unicast is 1-to-1.

Explore over-the-top routing in named mode, creating a single domain across any WAN by focusing on reachability, using BGP, VRF, VPNv4 address family, MPLS, and Lisp.

Explore how reported distance and feasible distance determine the best path, how the composite metric is calculated from the vector metric, and how feasible successors enable equal cost load sharing.

Learn how the classic metric is calculated by simplifying to bandwidth plus delay (K1 and K3 enabled) and multiplying the result by 256 to derive the routing feasible distance.

In named mode, compute wide metrics from bandwidth and delay constants to obtain feasible distance for route selection, including the impact of metric rib scale and 64-bit versus 32-bit metrics.

Explore general operations of a routing protocol, contrasting classic mode and named mode, 32- and 64-bit metrics, and adjacency formation via network statements.

Learn how to view and adjust timers for faster links by configuring hello interval and hold time, using classic and named mode under the ipv4 address family, with practical commands.

Configure a default route in EGP either by a static route redistributed into EGP or by a summary address on the interface, for IPv4 and IPv6.

Understand how stuck in active happens when a route's successor is lost without a feasible successor, triggering SIA queries and replies to locate a new path.

Explore HP's graceful shutdown for maintenance, allowing neighbors to reconverge routes when you reboot, and avoid 15 seconds of potential traffic black hole.

Learn how to implement stub routing on Cisco routers to stop query propagation while still advertising connected and summary routes, using receive-only and redistribute connected options.

Discover how leak maps selectively leak prefixes from summary routes and stub configurations, using route maps and acls to control advertised prefixes.

Explore how Cisco express forwarding drives traffic using multiple next hops stored in the rib, enabling equal and unequal cost load balancing with EGP, variance, and topology insights.

Explains add path for hub-and-spoke vpn networks, enabling up to four best hops to a prefix and updating from classic to named mode on iOS X devices.

Explore IPv4 and IPv6 address families in named mode, learn that unicast is default, multicast is for PIM, configure via address family, redistribute connected, and verify adjacencies across routers.

Learn how fast reroute precalculates a loop-free alternative to provide immediate backup routes in equal-cost multipath networks, accelerating failover when an adjacency fails.

Explore vrf lite and named-mode vrfs to isolate multi-department networks, configure ipv4 and ipv6 address families, route distinguishers, and vrf forwarding on interfaces for secure layer 3 vpn.

Understand how administrative distance governs route selection for summary, internal, and external routes, and learn to tweak distances with the distance command and redistribution in IPv4 and IPv6.

Explore how EGP, a distance vector protocol, uses hop count to filter routes. Configure maximum hops and observe how routes beyond the limit are dropped in testing adjacencies.

Apply offset lists to filter routes by adding metrics in the inbound or outbound direction, observe how the rib changes while the topology table remains populated.

Filter routes using distribute lists in inbound or outbound directions, with named ACLs or prefix lists, gateway options, and route maps to control neighbor updates and metrics.

Redistribute between EGP and RIP in a distance-vector network, manage external versus internal routes, assign metrics, and use route maps to control redistribution across both directions.

Examine redistribution with BGP, showing how to exclude loopback zero via a route-map when redistributing IGP into BGP, and fix adjacency flaps caused by AD conflicts to ensure full reachability.

Master mutual redistribution between OSPF and EGP in both named and classic modes, using route maps and metrics to ensure reachability from router six to router seven.

Learn manual summarization to improve routing stability and reduce routing table load by configuring ip summary address, disabling auto summarization, and using cidr in classic and named modes.

Learn how bidirectional forwarding detection (bfd) quickly detects link failures, reports to routing protocols, and enables millisecond convergence by using control and echo packets with tunable timers.

Explain how suboptimal routing occurs and how to solve it dynamically using route tagging in mutual redistribution between iBGP and OSPF, preventing routing loops and ensuring correct route selection.

Set up md5 authentication for vrf-based neighbors by creating keychains for R2 and R3 and applying md5 under the address family, in both named and classic modes, to reestablish adjacency.

Leverage named mode with 256-bit hmac authentication to protect updates, using a shared key, source ip, and update data to compute a hash that must match on both sides.

Explore how OSPF uses type 1 router LSA to announce directly connected links within an area, building the link state database and shaping next hop routing.

Explore OSPF type 2 network LSAs, the designated router flooding them within an area, and building the network map in the link state database.

Learn how OSPF type 3 LSAs summarize area routes via ABRs, linking area zero with non-backbone areas, and distinguish inter-area from intra-area routes in the database and routing tables.

explore ospf lsa types 4, 5, and 7, including asbr and abr roles, redistribution of connected routes into ospf, and not so stubby area behavior.

Explore ospf network types, including broadcast and non broadcast, and how designated router (dr) and backup designated router (bd-r) elections shape adjacencies through hello packets and timers.

Explore ospf area types, including the backbone area zero, transit areas, and stub variants, with abr behavior, type 3/5/7 lsas, and default routing.

Explains OSPF route types and LSA types, showing intra-area and inter-area routes (type 1, 3, 5, 7), ABR involvement, and external E1/E2 and not so stubby N1/N2 behavior.

Explore OSPF neighbor relationships, packet types, and the states from down to full, including hello, database descriptor, LSR, LSU, and ACK exchanges, plus master–slave decisions and MTU implications for adjacency.

Troubleshoot OSPF adjacencies by confirming area, timers, network type, and sub flags, and ensure mtu/m2, authentication, and subnet alignment; use CLI debugs to identify failures.

Explore OSPFv3 address families to route IPv4 and IPv6, configure adjacency, enable IPv6 unicast routing, and perform mutual redistribution between IPv4 and IPv6 in a practical lab.

Explore how ospf virtual links connect abrs through a transit area to carry type 3 summary lsas to area zero, illustrating why virtual links are a nonproduction band-aid.

Master OSPF path preference and area design to ensure optimal routing, considering LSA types, intra-area vs inter-area, E1/E2 and N1/N2 decisions, with equal-cost load balancing and auto-cost bandwidth.

learn how to perform graceful restart and graceful shutdown in OSPF to maintain adjacencies during maintenance, signaling departure with hello packets, preserving neighbor state, and rapid reconvergence.

Protect OSPF with TTL security to guard against denial of service attacks and adversarial process id events by validating TTL values for adjacencies.

OSPF LSA throttling speeds reconvergence from five seconds to milliseconds by using initial start, dupe LSA hold, and max hold timers; tune minimum LSA arrival and minimum LSA interval.

Explore SPF throttling in OSPF, batching LSA updates into the LSDB to stabilize convergence during link flaps, and tune timers to set initial delay, hold, and max wait.

Tune OSPF fast hellos by adjusting hello and dead intervals for point-to-point and multipoint links, then set retransmit and fast hello multipliers to improve convergence.

Learn how to configure an OSPF default route as a last resort, including always originate vs safety methods, and filter to permit only 0.0.0.0/0 using prefix lists and distribute lists.

Explore how to adjust OSPF administrative distance to influence path choice using the distance command, either by router ID or by route type (intra, inter, external).

Explore how to configure ospf in a vrf, covering area zero backbone requirement, the down bit, and remedies like virtual links or vrf lite to prevent loops.

Understand how OSPF distribute lists filter the routing table, not the link-state database or LSAs, and how area synchronization affects route visibility.

Apply OSPF filter lists at ABRs to control inbound or outbound type 3 summary LSAs between areas, using a prefix list to filter prefixes and protect area boundaries.

Explore redistributing between OSPF and BGP, using route maps to selectively import and export routes, including loopbacks, avoid flapping, and preserve interdomain reachability across iBGP and eBGP.

Explore configuring mutual redistribution between OSPF and EIGRP using named and classic modes, including metrics, route maps, and subnet handling to achieve reachability between remote OSPF and EIGRP domains.

Explore mutual redistribution between OSPF and RIP version 2 by forming adjacencies, manually setting metrics, and redistributing connected routes while comparing link-state versus distance-vector behavior.

Learn to configure OSPF summarization using area range and summary address, identifying the originating area via ABR/ASBR and the LSA types 1, 3, 5, and 7 that drive the LSDB.

Explore bidirectional forwarding detection (BFD) to rapidly detect link failures, report to routing protocols like OSPF or BGP, and cut convergence time to milliseconds with control and echo packets.

Tackle suboptimal routing between OSPF and EGP during mutual redistribution by using route tagging and route maps to block undesired routes and ensure correct next hops.

Enable OSPF passive interfaces to stop adjacencies while advertising networks as intra-area routes. Use passive default and selective no passive on interfaces to control adjacencies in area zero.

Learn how to configure OSPF clear text authentication on a per-neighbor interface, set the key, and verify adjacency with debugging, noting it is not for production.

Explore MD5 authentication in OSPF, hashing passwords with packet contents to prevent cleartext exposure and replay attacks, using key IDs and keychains for secure configuration.

Learn to enable ospf authentication with a keychain, using hmac-sha256, managing key IDs and lifetimes, and applying the keychain on interface e00 for adjacency.

Demonstrates OSPFv3 IPSec authentication to encrypt and verify neighbor sessions, using per-interface and per-area options, with SPI and triple des and sha1 configurations.

Explore BGP, the exterior gateway protocol that interconnects autonomous systems via a path vector model. Learn how weight, local preference, and AS path guide unicast routing.

Learn to form basic BGP peerings between R1, R3, and R5 using loopback neighbors, update-source loopback, and network statements within an internal and external AS context.

Learn the differences between ibgp and ebgp and how to troubleshoot bgp with loopback-based peering, route reflectors, confederations, next-hop self, and multihop concepts.

Learn how four-byte ASNs expand beyond two-byte numbers, and how AS plain and AS dot formats, compatibility fields, and the new AS path enable backward-compatible BGP.

Master the BGP neighbor states and the two-phase process. Understand TCP reachability in idle, connect, and active, then BGP open, open confirm, and established with keepalives and updates.

Learn to control who initiates the BGP TCP handshake by configuring active and passive transport modes between neighbors (port 179) and verify with show commands.

Explain BGP timers: keepalive every 60 seconds, hold down time three times the keepalive, and advertise interval differences for iBGP and eBGP (0 vs 30 seconds), including per-neighbor timer negotiation.

Configure dynamic neighbors in BGP using a peer group and listen range to automatically form adjacencies with inbound requests, simplifying hub-and-spoke deployments.

Learn how to advertise a default route in BGP using default information originate or per-neighbor methods, with static routes, redistribution, next-hop self, and prefix filtering.

Learn how administrative distance affects BGP route selection, comparing internal and external distances (EGP), with scenarios using redistribution and ACLs to illustrate AD tweaking.

Explore how to run BGP inside VRFs with VRF lite, create VRFs, assign interfaces, and use address families for IPv4 and IPv6 with route distinguishers and redistribution.

Apply route-maps to filter BGP prefixes by matching ACLs or prefix lists, understand inbound vs outbound order, and apply the route-map per neighbor to control learned routes.

learn how to filter bgp updates with filter lists, applying route maps, prefix lists, and distribute lists in inbound and outbound directions, using regular expressions to match as-paths.

Filter BGP prefixes per neighbor with prefix lists; deny 192.168.5.0/24 (less than 32) and permit the rest, configured inbound or outbound.

Filter BGP prefixes with distribute lists, choosing inbound or outbound directions, globally or per neighbor, using ACLs or prefix lists, including standard and extended options.

Explore how to redistribute between OSPF and BGP, using route maps to control external routes, E1/E2 and NSA area types, and achieve mutual redistribution across area zero and iBGP/BGP boundaries.

Redistribute RIP version two into BGP and back, manage loopback reachability, and control routes with a route map and metrics to prevent routing loops.

Redistribution with eigrp and bgp exposes loopback-related flaps when redistributing ospf/igp into bgp; apply route maps to deny loopback zero, enabling full reachability.

Explore bidirectional forwarding detection (bfd), quickly detect link failures, and speed routing protocol convergence to milliseconds using control and echo packets over UDP.

Learn how to configure BGP MD5 authentication with a per-neighbor password, understand its place in the TCP header, and troubleshoot adjacency by addressing authentication errors.

Explore how to use BGP peer groups to template adjacency settings, apply outbound and inbound policies, and manage attributes like remote AS, update source, and local preference across multiple neighbors.

Explore BGP templates and how they split configuration into session and policy templates, use inheritance to reuse settings, and compare templates with traditional peer groups to simplify neighbor management.

Understand the BGP attribute categories—well known mandatory, well known discretionary, optional transitive, and optional non transitive—and how they influence path selection as path, next hop, origin, and local preference.

Explore the BGP best path selection process, including next hop reachability, weight, local preference, as-path, origin, med, neighbor type, and the IGP metric, and how these attributes shape multipath routing.

Explore how BGP weight, applied inbound via neighbor or route-map, steers the best path for prefixes like 10.2435.0/24, noting Cisco proprietary, nontransitive behavior.

Explore local preference in bgp, its well known discretionary nature, the default 100, and apply it per prefix with route maps and acls for inbound or outbound paths.

Configure BGP with locally originated routes to influence best path selection by redistributing connected prefixes and using a 10.0.0.0/8 aggregate; compare network command versus summary and verify path with trace.

Demonstrates how to influence bgp best-path selection through as-path prepend, using route maps and acls to manipulate as path length and steer traffic among r1, r2, and r3.

Examine the BGP origin attribute and its impact on best path decisions, including how IGP, redistribution, and as-path prepend shape next-hop selection.

Learn how med, or multi exit discriminator, guides BGP best-path selection, including when to compare med for the same AS and how deterministic med enforces it, favoring the lower med.

Explore conditional advertisements in BGP, using an advertise map with exist and non exist conditions to dynamically steer prefixes to primary or backup service providers based on reachability.

Outbound route filtering (ORF) uses a prefix list and RF capability to offload route filtering to the service provider. Configure per neighbor on external sessions to minimize local resource use.

Explore how BGP private communities work as optional transitive attributes, and learn to configure them with route maps, including private versus well-known communities, additive updates, and the new format.

Learn how standard BGP communities control route propagation and loop prevention. Explore no export, no advertise, local-as, and extended communities as route targets that aid MPLS and layer 3 VPN.

Explore multihomed and single-homed networks, learn how two ISPs and edge routers affect BGP routing, including private vs public ASNs, local preference, and weight. Preview multipathing in the next video.

Explore route reflectors in BGP, replacing full mesh with a hub-and-spoke design, using the originator ID and cluster list to prevent loops while reflecting updates between route-reflector clients.

Explore how BGP confederations split the network into sub autonomous systems to avoid full mesh, detailing intra confederation and external sessions and how as confed attributes guide routing.

Learn how BGP aggregation advertises a summary route with an aggregate address, removes the AS path, uses as-set to preserve AS information, and employs summary-only, suppress and unsuppress maps.

Demonstrates multiprotocol BGP for layer 3 vpn and mpls, using ipv4, ipv6, and vpn address families, with route reflectors, activation, and redistribution to enable vpnv4 and vpnv6 routing.

Hide your autonomous system in BGP using the local as feature to present different as to neighbors. Use no prepend and replace as with allow as to preserve route validity.

Explains how allowas-in bypasses BGP loop prevention to accept updates containing the local AS, demonstrates reachability across MPLS layer 3 VPN, and warns of potential loops.

Learn to hide private autonomous systems in BGP by using remove private as on outbound updates, replacing private AS with your local AS and optionally all private AS numbers.

Demystify regular expressions for networking by mastering core symbols such as . ^ and $, learn grouping, and apply as-path filtering in BGP with route maps.

Learn how to implement multipathing in BGP through multihoming with two service providers, using prefix filtering and BGP best path multipath to install dual paths while avoiding transit autonomous systems.

Learn how BGP synchronization controls route advertisement between IBGP and IGP, and how redistributing BGP into IGP affects reachability when synchronization is enabled.

Learn how BGP soft reconfiguration stores updates in memory to refresh inbound or outbound routes without dropping the session, and how adjacency in, local rib, and the routing table interact.

Enable SNMP traps for BGP by configuring SNMP MIB support, selecting traps and state changes, and applying version 2 and max prefix thresholds.

Explore ipv6 basics in bgp, including link-local and global unicast addresses, eui-64 formation, and ipv6 reachability, then configure ipv6 bgp between two routers with various address-family scenarios.

Enable prefix independent convergence in bgp to install a backup path for rapid failover, avoiding multipath while preserving the primary route.

Explore how BGP next-hop address tracking, on by default, verifies reachability of next hops and removes unreachable prefixes, while tuning delays and applying next-hop filters with route maps.