Руслан Савченко, инструктор онлайн-школы SkillFactory – о самом интересном из программы курсов CCNP Route и CCNP Switch от Cisco и о том, какие знания в области маршрутизации и коммутации нужно иметь, чтобы решать по-настоящему сложные задачи.
2. #
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
3. #
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
8. #
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
9. #
Trunk Configuration
Configure VLANs
Disable trunk negotiation
Configure trunk mode
Set native VLAN to unused VLAN
Allow only required VLANs on trunks
10. #
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
11. #
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
12. #
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+
13. #
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
14. #
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
15. #
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
16. #
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
18. #
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
27. #
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
31. #
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
32. #
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
33. #
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
34. #
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
35. #
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
38. #
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
40. #
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
41. #
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
43. #
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
45. #
BGP Path Selection Decision Process
Consider only (synchronized) routes with no AS loops and a
valid next hop, and next steps for evaluation are: