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--- networking:clos [2026/04/07 10:43] – [Optics] v1ctor
+++ networking:clos [2026/04/07 13:26] (current) – [ROUTING] v1ctor
@@ Line 38: / Line 38: @@
 In general, you don't want deep buffers in the fabric, because most applications prefer to drop traffic rather than queue it.
+Bufferbloat occurs when excessively large switch/router buffers absorb traffic bursts instead of dropping packets, hiding congestion signals from TCP (or other transport protocols). The result:
+  - Latency spikes — packets sit in deep queues for milliseconds to tens of milliseconds instead of being delivered or dropped promptly.
+  - Reduced throughput — TCP's congestion control reacts too late because loss signals are delayed.
+  - Jitter — unpredictable queue depths cause variable RTTs.
+==== ROUTING ====
+There are three main designs:
+  - iBGP underlay and eBGP overlay
+    - Spines and Super-spines are in iBGP domain
+    - Each leaf has its unique ASN assigned
+    - Leaves establish multi-hop eBGP with each other
+  - eBGP underlay and iBGP overlay (Juniper way)
+    - All leaves share the same ASN
+    - Spines and super-spines are connected using eBGP
+    - Leaves are connected using iBGP
+  - eBGP for both
+BGP convergence challenges:
+  - Path hunting
+  - Over-flooding
+Solutions:
+  - Valley-free routing - make sure leaves are non-transit routers. One of the solutions is to apply outbound AS-path filter allowing only ''^$''
+BGP Tuning options:
+  - MRAI (Min route advertisement interval)