2021-01-16 15:06:53 +01:00
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# -*- fill-column: 76; -*-
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#+Title: BNG - Linux router project
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#+Options: ^:nil
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This git-repo (goal is to) contain tools and designs for a Broadband Network
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Gateway (BNG) router based on Linux.
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2021-08-18 15:21:31 +02:00
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We assume a setup like this:
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#+begin_src
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+--------------------------+
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| BNG |
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<------+eth1 eth0 +-----> Upstream internet
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Customer <------+eth2 |
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interfaces | |
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|... |
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<------+ethX |
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+--------------------------+
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#+end_src
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Where the BNG box is a middlebox between one or more customer-facing
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interfaces, and an upstream connection. The customer interfaces use
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double-tagged VLANs where the outer VLAN tag determines the Point of
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Presence that the customer is connected to, and the inner VLAN tag is unique
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per customer.
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This setup should be transparent to the customer equipment, which means the
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BNG needs to add and remove VLAN tags for the traffic as needed, and do
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NAT'ing for IPv4 traffic. From the customer PoV it should appear like they
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are on their own layer-2 segment with the BNG being the only other host. It
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also needs to relay DHCP traffic to an upstream central DHCP server.
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Functions in scope are:
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- DHCP relay for v4 and v6
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- NAT'ing of traffic (for IPv4) and routing of customer prefixes (for IPv6
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with prefix delegation)
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The idea is to use regular Linux stack functionality as much as possible
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(e.g., VLAN interfaces), but accelerate functions with XDP and TC-BPF where
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appropriate, for either functionality or performance reasons.
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