Source-Based Routing; Without Source-Based Routing; With Source-Based Routing - Paradyne 8540 Network Configuration Manual

IP Routing

Source-Based Routing

Without Source-Based Routing

With Source-Based Routing

6-10
In addition to destination-based routing, the HotWire DSLAM system also
supports source-based routing. Source-based routing is a security feature for
preventing ES-to-ES routing when they are attached to different RTUs that are
attached to the same DSL card. That is, sourced-based routing can ensure that
all upstream traffic within a service domain is sent to the NSP.
The following illustration shows that with destination routing ES1 can send
packets to ES2 based on the static route table. That is, when ES1 sends a packet
to ES2, the destination route is 155.1.3.5 and the next hop address for this
destination is 135.1.3.4 (RTU 2).
DSL Card*
Router
155.1.3.1
*If DSL card is an 8540 DSL card,
associated RTU will not have an IP address.
DSL Routing Table
Host/Net Subnet Mask
1) 155.1.3.4 255.255.255.255
2) 155.1.3.5 255.255.255.255
3) 0.0.0.0 0.0.0.0
With source-based routing, the source address of upstream packets sent from an
ES are compared to the source address listed in the static route table. If a match
is found, the packet is sent to the next-hop address specified for that source
address.
The following illustration shows the packet flow when ES1 sends to ES2, and
when source-based routes are defined for ES1 and ES2 (indicated by the S/D
flag).
November 1997
RTU 1*
s1c
135.1.3.3
RTU 2*
135.1.3.4
s1d
8540 DSL 8546 DSL
Card Next-Hop Card Next-Hop
Address Address
s1c 135.1.3.3
s1d 135.1.3.4
155.1.3.1 155.1.3.1
ES1
155.1.3.4
Packet Flow
ES2
155.1.3.5
S/D (Source/
Destination)
dst (destination)
dst (destination)
dst (destination)
97-15472-02
8000-A2-GB21-20