Which Features Need More RAM on ISR1K 4 GB Branch Routers?
Which two features must an engineer consider while selecting the ISR1K with 4 Gb of memory for branches? (Choose two.)
Community Insight
The question tests hardware memory requirements for SD-WAN Edge security features, and the trap is assuming that a feature running on-box (like Zone-Based/Enterprise Firewall) is the one constrained by the 4 GB figure rather than the two features that explicitly require 8 GB DRAM.
Cisco Catalyst SD-WAN WAN Edge security services such as URL filtering and Cisco AMP/AMP Threat Grid impose minimum DRAM requirements on ISR 1000 branch routers, and both demand at least 8 GB of memory. This page establishes that selecting an ISR1K with only 4 GB of memory forces the engineer to weigh these two features, making B and C the correct pair.
Option A (Enterprise Firewall) is the most common wrong pick, because learners reason that a local zone-based firewall can run on the ISR1K with 4 GB and therefore 'must be considered'; the requirement wording, however, points to the two features whose official minimum is 8 GB DRAM, which is URL filtering and Cisco AMP.
Community Discussion (9 comments)
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Expert Analysis
Why the Answer Is Correct
Cisco documentation for Cisco Catalyst SD-WAN WAN Edge security services states that Cisco AMP (with AMP Threat Grid) requires a minimum of 8 GB of DRAM and 8 GB of system flash, and URL filtering also requires 8 GB of DRAM and 8 GB of flash for cloud lookups (16 GB DRAM/flash for on-box database lookups). Because both features are therefore unavailable on an ISR1K provisioned with only 4 GB of memory, they are exactly the two items an engineer must weigh before ordering that platform for a branch. Neither is a separate appliance or a controller function: both are locally enforced SD-WAN Edge security services tied to the Unified Threat Defense engine on the router. D3n1s's posted requirement table and Kojy's follow-up that both features need 8 GB+ directly support this. Consequently, B and C form the only pair whose memory floor exceeds the selected 4 GB configuration.Why the Other Options Are Wrong
Option A, Enterprise Firewall, is rejected because the ISR1K's zone-based/Application-Aware firewall features run within the 4 GB envelope and are not memory-blocked, so they are not a limiting constraint of this selection; jstaruch clarified that Enterprise Firewall "is not the same as Zone Based Firewall" and effectively implies a separate box in this context. Option D, the vSmart Controller, is a control-plane component that runs as a virtual or physical controller instance, not as a feature of a branch ISR1K, so it is irrelevant to branch router sizing. Option E, Cisco Umbrella DNS Security, is a cloud-delivered DNS-layer service reached by redirecting DNS queries, consuming negligible local DRAM and thus imposing no 8 GB-style requirement on the branch router. Option F does not exist here, and no other combination matches the documented 8 GB minimums.Community Comment Notes
D3n1s pasted the exact DRAM/flash minimums for AMP and URL filtering, which is the authoritative anchor for the pair BC. Kojy reiterated twice that "FOR SURE URL FILTERING & CISCO AMP NEED +8GB" and later stated "NO IT IS B&C BECAUSE ITS NEED 8GB+", consistent with the documentation. cc37f90 framed it as a consideration problem: "Main part of the question is 'consideration'. When choosing a router with 4Gb, you should consider that ULR Filtering and AMP needs 8Gb". A minority view (1d03e21 and jstaruch's earlier note) argued for A and B on the grounds that URL filtering has basic on-box support, but that reasoning ignores the explicit 8 GB minimum that the question is testing.Exam Strategy
On hardware-sizing items, look for the feature whose documented minimum resource exceeds the spec given in the stem; that mismatch is what 'must consider' is signaling. Eliminate controller-only and pure-cloud services immediately, since they are never part of branch router memory planning.
Frequently Asked Questions
Why is Enterprise Firewall not one of the two features to consider for an ISR1K with 4 GB?
The ISR1K's local zone-based/Application-Aware firewall runs within 4 GB of DRAM, so it is not blocked by the memory limit. Only URL filtering and Cisco AMP carry an 8 GB DRAM minimum, which is what the selection constrains.
Do URL filtering and Cisco AMP need 8 GB of RAM on every SD-WAN branch router?
Yes for those services: Cisco AMP requires 8 GB DRAM and 8 GB flash, and URL filtering needs 8 GB DRAM/flash for cloud lookups (16 GB for on-box database lookups). A 4 GB ISR1K cannot host them.
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