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Computer Networks → Introduction to Computer Networks 20

IP Fast Reroute LFA provides
Loop-free alternate paths for sub-50ms recovery
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TI-LFA uses segment routing for
100 percent coverage for IP FRR
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IPFRR RLFA uses
Remote LFA via tunnel to repair node
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IP FRR activation time is
Sub-50ms using pre-computed backup
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MPLS FRR protection types are
Link and node protection
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BGP large communities have
64-bit values (3 x 32-bit integers)
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BGP extended communities have
64-bit values
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BGP standard communities have
32-bit values (AS:value)
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BGP Graceful Restart helper assists
Restarting peer by maintaining forwarding during reconvergence
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BGP PIC (Prefix Independent Convergence) improves
Convergence time by pre-computing alternate BGP paths
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BGP maximum-paths enables
ECMP load balancing across multiple BGP paths
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BGP shutdown community signals
Planned maintenance to allow clean preprovide withdrawal
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BGP blackhole community triggers
Upstream provider to null-route traffic (DDoS mitigation)
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BGP aggregate-address creates
Summary route from more specific routes
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BGP suppress-map with aggregate hides
Specific routes covered by aggregate selectively
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Multicast group join uses
IGMP (IPv4) or MLD (IPv6)
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IGMP v1 leave group uses
Timeout - no explicit leave
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IGMP v2 adds
Explicit leave group message
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IGMP v3 adds
Source filtering (SSM support)
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PIM-SM uses
Shared trees with RP and source trees
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Computer Networks → Routing Algorithms 10

OSPF external metric E1 adds
Internal OSPF cost to external route metric
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OSPF external metric E2 does not add
Internal OSPF cost to external route metric
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OSPF database overflow protects
Router from excessive LSA flooding
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OSPF flood reduction reduces
LSA refresh flooding in stable networks
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OSPF stub area blocks Type
5 and 4 LSAs (external routes)
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OSPF totally stub area blocks Type
3 4 and 5 LSAs
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OSPF NSSA allows Type
7 LSAs (converted to Type 5 at ABR)
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OSPF totally NSSA blocks Type
3 4 5 but allows Type 7
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OSPF route preference IA vs E1 vs E2 order is
IA then E1 then E2
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OSPF area 0 requirement can be bypassed using
Virtual link through non-backbone area
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Computer Networks → Transport Layer 10

TCP initial window size is
10 MSS or 14600 bytes per RFC 6928
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TCP cubic is default in
Linux kernel
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TCP BBR (Bottleneck Bandwidth RTT) is
Google-developed model-based congestion control
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TCP Vegas uses
RTT change as congestion signal
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TCP RACK (Recent ACK) improves
Loss detection using time rather than just ACK counting
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TCP TFO (TCP Fast Open) allows
Data in SYN packet using pre-negotiated cookie
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TCP ECN (Explicit Congestion Notification) allows
Network to signal congestion without dropping packets
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TCP delayed ACK coalesces
Up to 2 ACKs to reduce overhead
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TCP receive buffer auto-tuning
Grows buffer based on BDP
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TCP send buffer should be at least
Full BDP (bandwidth delay product)
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