642-887 - Implementing Cisco Service Provider Next-Generation Core Network Services (SPCORE)
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When configuring LLQ (strict priority queue) on a traffic class using the Cisco IOS XR priority command on a Cisco ASR9K router, which additional QoS command is required for this traffic class?
The Cisco IOS and IOS XE qos pre-classify command allows which kind of packet classification on IP packets that are encapsulated with GRE and IPsec?
allows for packets to be classified based on the packet header parameters other than the ToS byte values after packet encryption
When a link flaps, an mpls ldp session will also flap. Which feature minimizes traffic loss and provides faster convergence after the link is re-established?
LDP session protection
Which Cisco IOS XR command should be used to identify if MPLS TE FRR is enabled?
show mpls traffic-eng tunnel <tunnel#>
When troubleshooting LDP operations on the Cisco IOS and IOS XE routers, what is one of the first things that should be verified?
check if the ip cef command has been enabled
On the Cisco IOS XR, when using the match protocol command within a class-map to classify traffic, you noticed that the match protocol option on the Cisco IOS XR shows much fewer protocol options than on the Cisco IOS or IOS XE, like there is no option such as the match protocol yahoo-messenger command on the Cisco IOS XR. Why is this?
because NBAR is not supported on the Cisco IOS XR
On Cisco routers, which three methods can be used to map traffic into the MPLS traffic engineering tunnel? (Choose three.)
What is the term that is used for the label that an LSR assigns and distributes to other LSRs in MPLS?
Which are typical class-based marking policies that are implemented on service provider IP NGN PE routers?
On the PE ingress, classify the customer traffic and then mark with qos-group. On the PE egress, classify based on the qos-group and then mark with mpls exp.
Which three network services can be implemented using MPLS within the service provider IP NGN core? (Choose three.)
Layer 2 VPNs
Layer 3 VPNs
Cisco MPLS TE path setup can be affected by which three tunnel attributes? (Choose three.)
When implementing Cisco MPLS TE, the constrained-based path calculations will use which value as the TE cost of each link within the MPLS domain?
By default, it will use the IGP metric, or each link can be assigned a specific value using the admin-weight command.
Implementing IPoDWDM interfaces on Cisco CRS routers eliminates the need for which network component?
On the Cisco IOS XR, which MQC configuration is different than on the Cisco IOS and IOS XE?
On the Cisco IOS XR, LLQ can be applied in the input or output direction.
Layer 2 VPN services that are offered by traditional service providers using a SONET/SDH backbone can be implemented by service providers using an IP/MPLS backbone with which MPLS feature?
Which affinity value will be matched by the affinity bit mask of the affinity 0xFF00000A mask 0xFFFF000F command?
On Cisco routers, how is hierarchical QoS implemented?
Within the parent policy-map, reference another child policy-map using the service-policy command.
Cisco MPLS TE resource attributes that are configured locally for each link are distributed to the headend router of the traffic engineering tunnel using which protocol?
OSPF or IS-IS with TE extension
Which two statements are correct in describing ISP environments that are running IP/MPLS in the core network? (Choose two.)
The BGP next hops point to the PE routers, and only the PE routers are required to run BGP.
The PE and P routers run LDP to learn the labels for reaching the BGP next-hop addresses.
Which Cisco IOS XR command should be used in order to enable LDP-IGP synchronization for the ISIS IGP protocol?
RP/0/RSP0/CPU0:R1(config-isis-if-af)#mpls ldp sync
A DSCP value of 41 in decimal corresponds to which IP precedence value?
In which two Cisco IOS XR configuration modes can mpls ldp igp sync be configured? (Choose two.)
Which QoS mechanism is used for congestion avoidance?
What is an important requirement with MPLS applications like Layer 3 MPLS VPNs?
An end-to-end LSP is required between the PE routers.
Which two features are used to provide Cisco MPLS TE node and link protection? (Choose two.)
When using the tunnel mpls traffic-eng path-option 1 explicit name test command in Cisco MPLS TE tunnel configurations, the test explicit-path configuration will consist of a list of which values?
On the Cisco ASR9K router, when using the bandwidth command to specify the minimum guaranteed bandwidth to be allocated for a specific class of traffic, what will be used as the queuing algorithm?
On Cisco routers, which QoS marker is only locally significant?
When implementing MPLS TE tunnels on Cisco IOS XR routers, what is the tunnel setup and hold priority value range, and which value has the highest priority?
0-7, where 0 is the highest priority
On a Cisco router, when will the router actually reserve the bandwidth for the MPLS traffic engineering tunnel?
on the receipt of the RSVP Resv message
Which statement is correct regarding the default MPLS TTL behavior?
When an ingress edge LSR receives an IP packet, it will decrement the IP TTL field by 1; then it will copy the decremented IP TTL field into the MPLS Label TTL field.
Which Cisco IOS XR command should be used in order to enable LDP on all interfaces for which the IGP protocol is enabled?
RP/0/0/CPU0:R1(config-ospf)#mpls ldp auto-config
When defining an explicit MPLS TE tunnel path, which two command options are available under the explicit-path configuration mode? (Choose two.)
Which Cisco IOS XR high-availability feature is used to prevent routes from being used before LDP converges?
You are tasked to enable LDP on many of the interfaces on the Cisco CRS-3 router, and because there are many interfaces that need to have LDP enabled, you mistakenly did not enable LDP on all the required interfaces. To prevent this issue from happening again in the future, what could you do the next time you need to enable LDP on many interfaces?
use the mpls ldp auto-config command under the IGP routing process
Which three mechanisms are used to implement MPLS TE? (Choose three.)
Which two of the following statements are correct regarding LSPs? (Choose two.)
An IGP is used to populate routing tables in all routers in an MPLS domain.
LDP is used to propagate labels and build LSPs.
LDP session protection uses which one to maintain the LDP session between LDP neighbors?
backup-targeted LDP hellos
With unmanaged CE routers, at which point in the service provider network is the QoS trust boundary, and what is required at the trust boundary?
between the CE and PE router and mapping of the customer traffic classes into the service provider traffic classes at the PE router ingress
In Cisco MPLS TE implementations, what can cause the tunnel bandwidth to adjust automatically based on the traffic load in the tunnel?
When configuring class-based WRED on Cisco routers, which WRED parameter is not user configurable on a Cisco IOS XR but is user configurable on a Cisco IOS and IOS XE?
the mark probability denominator