5 продвинутых технологий

Cisco, которые нужно знать

Ruslan Savchenko

09.08.2013

rsavchenko@getccna.ru

ведущий:

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CCNP is: Routing: EIGRP, OSPF, RIP, BGP Switching Routing and switching troubleshooting

CCNP is NOT:

Voice Wireless Security Specific WAN protocols (MPLS,

advanced BGP)

What Is CCNP-R&S Coverage

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CCENT: install and verify basic IP network with supervision

CCNA: also… configure and maintain a multisite enterprise network, as directed

CCNP: also… plan and troubleshoot enterprise networks with advanced solutions, collaborating with network specialists

CCIE: also… independently troubleshoot and optimize network performance in complex and integrated enterprise networks

Certification for Network Engineers

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Cisco Career Certifications

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Switching (SWITCH)

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SWITCH is: Campus layer 2 management (VLANs, STP –all flavors) Campus layer 3 management (Inter-VLAN Routing, first hop

redundancy) Campus network management (network design, security,

voice) SWITCH is NOT: “Only layer 2” Deep wireless, security or voice

What Is Switch Coverage

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Enterprise Campus Architecture

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VLAN Deployment

End-to-end VLANs Users are grouped into VLANs independent of physical location If users are moved within the campus, their VLAN membership remains the same Local VLANs Recommended solution in the enterprise campus architecture Users are grouped into VLANs depending of physical location If users are moved within the campus, their VLAN membership changes

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Trunk Configuration

Configure VLANs Disable trunk negotiation Configure trunk mode Set native VLAN to unused VLAN Allow only required VLANs on trunks

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Common Trunk Link Problems

Trunks can be configured statically or autonegotiated with DTP For trunking to be autonegotiated, the switches must be in the same

VTP domain Some trunk configuration combinations will successfully configure a

trunk, some will not

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Issues with 802.1Q Native VLAN

Native VLAN frames are carried over the trunk link untagged Native VLAN must match at the ends of a trunk A native VLAN mismatch will merge traffic between VLANs Default native VLAN is VLAN 1 Configure an unused VLAN as native VLAN on trunks

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Spanning Tree Standards

802.1D-1998: The legacy standard for bridging and STP CST: Assumes one spanning-tree instance for the entire bridged

network, regardless of the number of VLANs PVST+:A Cisco enhancement of STP that provides a separate 802.1D

spanning tree instance for each VLAN configured in the network 802.1D-2004: An updated bridging and STP standard 802.1s (MST):Maps multiple VLANs into the same spanning-tree

instance 802.1w (RSTP):Improves convergence over 1998 STP by adding roles to

ports and enhancing BPDU exchanges PVRST+: A Cisco enhancement of RSTP using PVST+

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Spanning Tree Recommendations

Use PVRST+ or MSTP for best convergence

Take advantage of the Cisco STP toolkit

Keep STP domain as simple as possible

Do not disable STP—it protects against unplanned loops

Use routed links if possible

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Cisco STP Toolkit

PortFast: configures access port as edge ports which transition directly to forwarding state

BPDUGuard: disables a PortFast-enabled port if a BPDU is received

BPDUfilter: suppresses BPDUs on ports (not recommended)

RootGuard: prevents external switches from becoming roots

LoopGuard: prevents an alternate port or root port from becoming the designated port if no BPDUs are received

UplinkFast*: provides from 3 to 5 seconds convergence after link failure

BackboneFast*: cuts the convergence time by max_age for an indirect failure

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Process switching Slowest method—every packet examined by CPU, all forwarding decisions made in software Fast switching (route caching) Faster method—first packet in each flow examined by CPU, forwarding decision cached in hardware for subsequent packets in flow Cisco Express Forwarding (topology-based switching) Fastest method—hardware forwarding table created regardless of traffic flows, all packets switched using hardware Switching mode for multi-layer switches

Cisco Layer 3 Switching Methods

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Configure SVI and Routed Interface

switch(config)# ip routing switch(config)# interface vlan10 switch(config-if)# ip address 10.1.10.1 255.255.255.0 switch(config-if)# no shutdown switch(config)# interface vlan20 switch(config-if)# ip address 10.1.20.1 255.255.255.0 switch(config-if)# no shutdown

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HSRP Configuration

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HSRP and Spanning Tree

Configured active router should be the same as STP root bridge

Blocked uplink caused traffic to take less than optimal path

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GLBP Operation

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GLBP Weights and Decrements

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GLBP Configuration

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Routing (ROUTE)

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ROUTE is: IGP Routing: EIGRP, OSPF, RIP Path control: route maps, filters, redistribution, policy-based

routing ISP connection management: standard BGP IPv6 Branch offices and remote workers connectivity: VPN, GRE ROUTE is NOT: Voice Wireless Security Specific WAN protocols (MPLS, IS-IS, advanced BGP) Multicast

What Is Route Coverage

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Example: Enterprise network

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Routing Protocol Comparison

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OSPF. Link-State Protocols

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Link-state routing requires a hierarchical network structure: Transit area (backbone or area 0) Normal areas (non-backbone areas)

Area Terminology and Router Types

ABR:Area Border Router ASBR:Autonomous System Boundary Router R5, R6:Internal routers R1:Backbone router

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OSPF Packet Types

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Example of Different LSAs

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Types of Areas

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Design Limitations of OSPF

If more than one area is configured, one of these areas has be to be area 0—backbone area

All areas must be connected to area 0 Area 0 must be contiguous

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No Direct Physical Connection to Area 0

Area 20 added with no physical access to area 0 A virtual link provides logical path to the backbone The OSPF database treats the link between routers ABR1 and

ABR2 as a direct link

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Discontinuous Area 0

Two companies merge without a direct link between them Virtual links are used to connect a discontinuous area 0 A logical link is built between routers ABR1 and ABR2 Virtual links are recommended for backup or temporary

connections too

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EIGRP Capabilities and Attributes

Advanced distance vector Multicast and Unicast instead of broadcast address Support for multiple network-layer protocols 100% loop-free classless routing Fast convergence Partial updates Flexible network design

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EIGRP Capabilities and Attributes

Support for VLSM and discontinuous subnets Provides load balancing across equal-and unequal-cost

pathways Easy configuration for WANs and LANs Manual summarization at any point Sophisticated metric

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Example: EIGRP Tables

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Successor and Feasible Successor

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Example: Successor and Feasible Successor Solve Loop Issue

R1 receives information about the 10.0.0./8 from R8 and R4 FD on R1 is smaller than AD from R4 and the update from R4 is not FS

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Verifying EIGRP Neighbors

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Factors that Influence EIGRP Scalability

Amount of routing information exchanged between peers Number of routers Depth of topology—the number of hops that information must

travel to reach all routers Number of alternate paths through the network

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EIGRP Query Process Stuck-in-Active

The router must get replies to all its queries for a lost route to start calculating successor information If any reply to the query is lost or missing within three minutes: The route is SIA The router resets the neighbor relationship with the neighbor that fails to reply

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Enterprise Network to ISP Connection Options

Single-homed Dual-homed Multihomed Dual-multihomed

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BGP Routing Between Autonomous Systems

BGP is to provide an interdomain routing system BGP guarantees the exchange of loop-free routing information BGP works differently than IGPs BGP is a policy-based routing protocol Control traffic flow using multiple BGP path attributes

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Basic EBGP Configuration

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BGP Path Selection Decision Process

Consider only (synchronized) routes with no AS loops and a valid next hop, and next steps for evaluation are:

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Set AS Path with Route Map

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Redistribution Techniques

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Two-Way Multipoint Redistribution Issue

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Questions?

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Thank you!