Transcript Document

Routing Simulations – Zebra
Routing Software
Eric Ciocca
Dimitris Zacharopoulos
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Overview
Current Routing simulators
 Routing Software
 Benefits of simulators
 Limitations
 Testing the two software packages
 Conclusion

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Current Routing Simulators

Java SSFNet (SSF)
– Supports BGP (among others)
– Runs in Java

NS-2
– Multicast, various algorithmic routings
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Cnet
– Simulates general hosts/routers
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Routing Software

Regular Routers
– I.O.S. (Cisco’s Operating System)
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Under Unix O.S.
– In.routed (typical unix routing daemon)
– Gated (Another unix daemon)
– Zebra

Under Windows OS
– Integrated routing service
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Routing Software (cont.)

Unix Routing Software
– Routed
• supports only RIP and static routes
– Gated
• Static, RIP, OSPF, BGP4, IPv6
• Difficult configuration
– Zebra
• BGP, RIP, RIPng, OSPF v2, v3, IPv6
• Easy CLI, just like Cisco’s IOS
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Zebra Routing Software

Zebra makes your computer a router!
– And a Gateway router too!!
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Benefits
– Test new configurations
• New routing policies
• New protocols
– Don’t disturb the production network
– Use cheap PCs instead of expensive
routers
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Zebra Architecture
BGPd
RIPd
OSPFd
Zebra
routing
manager
UNIX Kernel
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Zebra features

Features
– Can handle unlimited # of Interfaces
– One process per one protocol
– Route Server & Route Reflector
integrated
– Multithread based technology
– Policy control and filtering
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The testing setup

For our experiments we use:
– 2 Solaris with two Ethernet cards each
– 1 Cisco 2514
– Zebra version 0.89
Cisco
Router
AS400
Solaris
Router B
AS2525
Solaris
Router C
AS2525
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Concept behind our test bed

We want to compare the communication:
– Router – zebra
– Zebra – zebra
– Router – router

What to test:
– Bgp4 sessions, (routing updates, keepalive)
– Route reflection
– Default route propagation
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Software simulation of BGP4

BGP simulation is a part of the
SSFNet simulator
– Allows simulation of arbitrarily sized
networks
– Incorporates most major features of
BGP
• Most recently added, route reflection
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Benefits of BGP Simulation

We are not restrained by physical
hardware
– We are able to simulate very large,
elaborate networks
– No purchasing of routers to test layout
– No modification of real routers to test
changes in policy
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SSFNet Specifics




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SSF=Scalable Simulation Framework
SSFNet Supports multiple protocols
(OSPF, BGP4, TCP, IP, custom) and
network entities (NIC, host, router)
Java SSFNet requires JDK1.2 or higher
DML models are system independent
Requires a discrete-event simulation
kernel
– A simulated one is available for free from
Renesys
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Simulated BGP4 Features

iBGP / eBGP are both supported
– iBGP supports route reflection
– Does not support confererations
Policy (route filtering) is mostly
implemented but untested
 Update handing is fully implemented

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What we have accomplished

For the physical simulations:
– Successfully achieved BGP peering
between all machines
– Added some static routes
– Exchange routing information
– Debug the protocols used
– Used both eBGP and iBGP
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What we have accomplished

For the software simulations:
– Successfully simulated BGP peering
between virtual routers
– Exchanged routing information between
BGP peers
– Used both eBGP and iBGP
– Simulated route reflection in a mediumscale network
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A quick example

Route propagation from left to right
X
X
Y
Z
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SSFNet Results
~#
~# = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
~# PROPAGATION Validation Test: successful if five steps
printed below
~# = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
~#
~# 1. AS X: sent route advertisement to AS Y
~# 2. AS Y: received advertisement from AS X
~# 3. AS Y: sending update to AS Z
~# 4. AS Z: received update from AS Y
~# 5. AS Z: route added to forwarding table
~# *** TEST SUCCESSFUL ***
~# ----------------------------------------------------------| 1 timelines, 5 barriers, 126 events, 365 ms, 1 Kevt/s
-------------------------------------------------------------18
Real network results
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TO DO

Route reflections
– Some problems with IBGP behavior

Override kernel routes
– We are unable to make changes to routes that
were installed by the kernel before we run zebra
– Need to check if this is regular behavior

Test bad gadget if we find more equipment..
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Conclusion
Zebra is far better than any other
routing software
 One process for each protocol
 Dynamic configuration changes
 Interactive queries (supports bgp
regexp table lookups)

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Conclusion
So far, the SSFNet simulator behaves
the same as a “real” network of BGP
peers
 Java SSFNet is a portable,
lightweight simulator which can
replace real-router modification for
network experimentation

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Thank You!

Zebra
– http://www.zebra.org

SSFNet
– http://www.ssfnet.org
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