1 Flashcards
What are two benefits of VRRPv3 over other FHRP protocols?
Multivendor support
IPv6 support
What group numbers can you configure with HSRPv1?
0-255
What group numbers can you configure with HSRPv2?
0-4095
What provides load balancing at Layer 3?
GLBP
What provides load balancing at layer 2?
VSS
What is the virtual MAC address for HSRPv1?
0000.0c07.acxx
What is the multicast address for HSRPv1?
224.0.0.2
How is the master router selected in VRRP?
Highest priority
Highest IP address
Which FHRP protocol maximizes uplink utilization?
GLBP
What is a difference between HSRPv1 and HSRPv2 in terms of timer configuration?
v2 supports millisecond timers
What is a configuration prerequisite when configuring Nonstop Forwarding?
SSO
What is not supported in Nonstop Forwarding?
IPv6 routing
IP multicast routing
HSRP
What problem does configuring SSO with HSRP solve?
Interruption of service in case of a failover
What is a FIB?
Forwarding Information Base
The actual information that a routing/switching device uses to choose the interface that a given packet will use for egress
How is a FIB populated?
By one or more RIBs
What is a RIB?
Routing Information Base
A selection of routing information learned via static definition or a dynamic routing protocol
Which QoS component can alter a packet, classification or marking?
Marking
What are some differences between policing and shaping?
Policing drops rather than buffers excessive traffic
Shaping can introducte latency issues
How does CEF make forwarding decisions
By using the FIB and Adjacency table
What uses a fast cache that is maintained in a router’s data plane?
Fast
Fast Switching
How does shaping handle network congestion?
Buffers and queues packets aboce the committed rate
Where should policing be performed?
As close to the source as possible
In SD-WAN, which component deals with the orchestration plane?
vBond
In SD-WAN, which component deals with the data plane?
vSmart
In SD-WAN, which component is the single plane of management?
vManage
In SD-WAN, what are some things vSmart does?
Implements policies created on vManage
Advertise routes, routers, security and policy information to edge routers via OMP
Establish secure control plane connections
In SD-WAN, what are some things vBond does?
Acts as a STUN server during the onboarding process of edge devices
Onboards vEdge notes into the fabric
Responsible for the zero-touch provisioning process
Shares information on how the network is connected
What is OMP?
Overlay Management Protocol
A control plane protocol used between SD-WAN routers and controllers
In SD-WAN, what is a VPN?
Virtualized environment that provides traffic isolation and segmentation in the fabric
How does priority work in HSRP?
Default priority is 100, can be configured 0-255
Highest priority takes precedence
What are some features about VRRP that are not true about all other FHRPs?
Pre-emption is enabled by default
Secondary IP addresses are supported with VRRP
GLBP is capable of what types of load balancing?
Round-robin (default)
Host dependent
Weighted
What is SSO?
Stateful Switchover
A redundancy feature that allows a supervisor engine to take over when the primary supervisor engine fails
When removing an active supervisor on a switch for maintenance, what mechanism ensures there is no downtime?
SSO
What are some considerations you should have when using SSO as a network redundancy feature?
Must be combined with NSF to support uninterrupted L3 operations
Requires synchronization between supervisors in order to guarantee continuous connectivity
What happens in a failover situation in a design situation where NSF is combined with SSO?
The standby route processor immediately takes control and forwards packets along known routes
What is best-practice for a core layer in a three-tier network design?
Provide redundant L3 point-to-point links between core devices for faster and more predictable convergence
What is routed access?
An alternate configuration where Layer 3 is extended to the access layer switches. No L2 links, so no STP required.
Facilitates a migration from a traditional campus design to a programmable fabric design
What architecture is commonly used in data centers?
Spine-and-leaf
What are some best practices when designing a campus L3 infrastructure?
Summarize routes from the aggregation layer toward the core layer
Tune CEF load balancing hash for ECMP routing
What are some network problems that would indicate a need to implement QoS?
Excess jitter
Packet loss (bandwidth related)
How is QoS packet classification performed?
By modifying the TOS field in the layer 3 header
How is the RIB derived?
From the control plane
What is stored in TCAM?
ACL and QoS information
What is TCAM used for?
For layer #3 address lookups
What are the modes for CEF?
Central CEF mode
Distributed CEF mode
What punts each packet?
Process switching
What is the differences between CEF and process switching in terms of what’s being used?
CEF uses dedicated hardware processors, process switching uses the main processor
What deployment model would you use if you wanted to manage several branches locally with CAPWAP?
Mobility Express
What is Cisco Unified Wireless Network?
A wireless solution that can support a main office and multiple branch locations. All sites would have local Internet connections and a link to the main office for corporate connectivity. The branch offices are managed centrally.
What wireless design should you use if you want the wireless network to be fully functional even if the WLC fails?
FlexConnect
What is DSCP?
Differentiated Services Code Point
DS is the six-bit portion of the IP header used to classify packets
In QoS, what is a policy map?
A mechanism to create a scheduler for packets prior to forwarding
In QoS, what is a service policy?
A mechanism to apply a QoS policy to an interface
In SD-WAN, what protocol is used to detect link failures and measure link quality?
BFD
Bidirectional Forwarding Detection
Enabled by default
What does the TOS field indicate?
The priority of a packet
In SD-Access, how is 802.11 traffic handled?
AP converts to 802.3
Encapsulated into VXLAN
What must match between routers in HSRP configuration?
Virtual IP address
Key-strings
Group numbers
What are the nodes in SD-Access?
Control plane
Fabric border
Fabric edge
Intermediate
WLC
When connected to a edge switch in SD-Access fabric, what decides if the client has access to the internet?
ISE
Identity Services Engine
In wiresless SD-Access, what provides radio resource management?
WLC
In SD-Access, what provides Layer 2 and 3 logical networks?
Overlay network
In SD-Access, what control plane protocol maps and resolves endpoints?
LISP
In SD-Access, what does the control plane node (CPN) do?
Tracks endpoint ID (EID) to edge node bindings
Holds a comprehensive database that tracks endpoints and networks in the fabric
In SD-Access, what does a fabric edge node do?
Connects endpoints to the fabric and forwards their traffic
In SD-Access, what does a fusion router do?
Enables VRF, leaking routes between user-defined virtual networks and shared services
In wireless SD-Access, what is part of the fabric overlay?
APs
In SD-Access, what does a fabric border node do?
Connects the SD-Access fabric to another fabric or external Layer 3 networks
In wireless SD-Access, what is Inter-xTR roaming?
Allows a client to roam from an AP to another AP on a different access-switch
What is the recommended MTU size for a Cisco SD-Access Fabric?
1900
In SD-Access deployment, what does VXLAN do?
Data plane forwarding
What is used in the policy plane of the fabric in SD-Access?
TrustSec
In SD-Access, what is the role of ISE?
It is leveraged for dynamic endpoint to group mapping and policy definition
In SD-Access, what does the DNA Center do?
Management
It is responsible for the design, management, deployment, provisioning, and assurance of the fabric network devices
What are the two types of data policy in SD-WAN?
Centralized - provisioned centrally on vSmart and affects traffic flow across entire network
Localized - provisioned locally on vEdge devices using access lists
What is LMP (Link Management Protocol)?
Activated on each link of the StackWise Virtual link to:
Verify link integrity by establishing bidirectional traffic forwarding/rejecting unidirectional links
Exchange periodic hellos for monitoring
