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These 10 free SRA questions are organized by exam domain, so you can see how each part of the Nokia Service Routing Architect blueprint is tested. Reveal the answer and explanation under each question.
A new internal SR OS router peers by iBGP with the Internet border's IGP-reachable system address. It accepts 203.0.113.0/24 but cannot install the route because NEXT_HOP 198.51.100.2 is unresolved. The border can forward to the destination. External peering subnets must remain outside the IGP. Which border-router change restores forwarding without changing that design?
Correct answer: C - Advertise the route internally with next-hop-self.
A route reflector selects a route received from non-client Edge1. Client Access1 receives it, but non-client Edge2 does not. All three iBGP sessions are established, and neither policy nor loop prevention rejects the route. Which route-reflection rule explains the difference?
Correct answer: C - Routes learned from a non-client may be reflected to clients, but not to another non-client.
An Ethernet pseudowire must carry a 1,500-byte customer IP packet. The customer's outer service-delimiting VLAN tag is removed; one inner VLAN tag is retained. The provider link carries three MPLS labels, a four-byte control word, and one outer VLAN tag. Ethernet headers are 14 bytes; each VLAN tag and MPLS label is four bytes. The provider link admits outer Ethernet frames up to 1,548 bytes, excluding FCS, preamble, and inter-frame gap. Both service MTUs are sufficient. Small frames pass, but the required maximum-size packet fails. Choose the correct diagnosis and required outer-frame allowance.
Correct answer: D - 1,552 bytes; enlarge the link allowance to carry the required encapsulated frame.
Three sites share a flat LDP-signaled VPLS. PE-A has a mesh-SDP binding to PE-B, and PE-B has one to PE-C; there is no PE-A-to-PE-C binding. MPLS transport connects every PE pair, and each existing service binding is operational. A-to-B and B-to-C customer traffic works, but A-to-C traffic fails even for small frames. The design must retain mesh split-horizon protection rather than turn PE-B into a transit bridge. Which change completes the design?
Correct answer: A - Add a mesh-SDP binding directly between PE-A and PE-C.
A shared-services VPRN hosts 172.18.50.0/24. Tenant Red exports 10.10.0.0/16 with route target 65000:110; Tenant Blue exports 10.20.0.0/16 with 65000:120. Both tenants import the shared-services route target 65000:900, but not each other's route target. The shared-services VPRN imports 65000:120 only and exports only its server subnet. A request from 10.10.1.5 reaches server 172.18.50.10, but the reply is discarded at the services PE, whose VPRN lacks 10.10.0.0/16. Select the repair that restores the reply path without enabling tenant-to-tenant routing.
Correct answer: B - Import Red's 10.10.0.0/16 carrying 65000:110 into the shared-services VPRN.
During a busy hour, a 7750 SR buffer pool reports 62% average shared-buffer utilization. Its enabled low WRED slope has start-avg 40%, max-avg 80%, and max-prob 20%; the enabled high slope starts at 75%. Out-of-profile TCP traffic accumulates WRED discards, while in-profile traffic meets its service-level agreement. Tail-drop, policer-drop, and physical-error counters are unchanged. An engineer proposes removing WRED because the pool is not full. How should these measurements guide the response?
Correct answer: D - Retain the slopes; these profile-selective early discards are consistent with the configured policy.
A customer handoff uses the color-blind two-rate three-color meter defined in RFC 2698. Just before two packets arrive, the committed bucket contains 800 bytes of tokens and the peak bucket contains 2,200. A 1,200-byte IP packet is followed immediately by a 700-byte IP packet, with no token replenishment between them. The policy forwards green packets in-profile, forwards yellow packets out-of-profile, and drops red packets. How is the second packet treated, and what token balances remain?
Correct answer: A - Green and forwarded in-profile; 100 committed and 300 peak bytes remain.
A customer is all-active multihomed to PE1 and PE2 in an EVPN-MPLS ELAN. PE1 is the designated forwarder for the service. A remote PE has valid aliasing paths through both PEs and sends different known-unicast flows through each. Both flows reach the customer, while only PE1 delivers broadcasts arriving from the remote network. No duplicate frames are observed. A technician flags PE2's unicast traffic as a fault. What response is warranted?
Correct answer: A - Keep both attachments active; this is valid all-active forwarding.
An SR OS EVPN-VXLAN service uses symmetric interface-ful numbered IRB through a supplementary broadcast domain (SBD). A remote tenant prefix remains unresolved despite this state: Type 5: 172.22.0.0/24; gateway IP 10.255.0.2; BGP next hop 192.0.2.22; accepted by tenant import policy. Underlay: the VTEP at 192.0.2.22 is reachable and VXLAN transport is operational. SBD: the only imported Type 2 MAC/IP binding is 02:00:00:00:00:33 with IP 10.255.0.3. What must be supplied to complete this prefix's overlay resolution?
Correct answer: B - An SBD Type 2 MAC/IP route for the advertised gateway, 10.255.0.2.
Minutes after an Internet-edge export-policy change, traffic from peer P2 toward destinations reached through peer P1 saturates the provider core. An emergency-dispatch voice service is losing packets. The AS is not contracted to provide peer-to-peer transit. Routing records confirm that P1-learned prefixes are now advertised to P2; previously, P2 received only the provider's own and customer prefixes. Both peerings still carry legitimate traffic. What is the first containment action that preserves those legitimate paths?
Correct answer: D - Restore P2's export filter and withdraw the leaked P1 routes.
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