Transcript Wireless ISP Infrastructure

Wireless ISP
Infrastructure
MikroTik
Director - John Tully
CTO – Arnis Riekstins
11 May, 2002
MikroTik
AP Platform
 multiple radios per AP
 Increase aggregate bandwidth using nonoverlapping frequencies
 Re-use of network configurations such as
firewalls and users
 Network services closest to the user
(PPPoE, DHCP, and PPTP)
11 May, 2002
MikroTik
From AP directly to client
(no router on client site)
 AP MAC registration table
 Assign IP to MAC with ARP disabled
 Restricted MAC level forwarding on
wireless network
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(cont) AP direct to client
 PPPoE access concentrator
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Overview
AC configuration demonstration
Window XP client configuration demonstration
Encryption – MPPE protocol, advantages in
wireless
 Radius authentication
 no engineer needed for account changes
 automatic billing with legacy systems
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(cont) AP direct to client
 Bandwidth setting
 Tx and rx settings allow you to simulate DSL offers
 Address assignment
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(cont) AP direct to client
 PPTP
 DHCP assigns private IP address
 PPTP on Windows
 PPTP clients available back to Windows 3.11
 Radius authentication
 Scripting to set bandwidth (in v2.6)
 Demonstration of setup, server and client
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From Wireless Client Router to
Client LAN
 General description of client site router
 Protects wireless network from hacking by
customers
 Offer services to customers
 Masqueraded address
 Static NAT for servers
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From Wireless Client Router to
Client LAN (cont)
 Multiple client connected to same router
 Per interface firewall
 Multiple ethernet interfaces in client site router
 Using a smart switch with router and VLAN
tags on a port basis (v2.6)
 Using an ethernet bridge and PPPoE or PPTP
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From Wireless Client Router to
Client LAN (cont)
 MikroTik Packet Packer Protocol (M3P)
 Wireless has high per packet overhead
 Negotiating access to wireless medium
 Acknowledgment and error correction
 M3P packs small packets into a large wireless
MAC packet and increase throughput up to
four times (with 100 byte packets)
 Automatically discovers other MikroTik routers
with this feature enabled
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MikroTik
From Wireless Client Router to
Client LAN (cont)
 Services to customers beyond an IP
gateway
 DHCP
 Special firewall configurations
 Per IP address accounting (even on
masqueraded addresses)
 Dedicated VPN tunnel between other offices
 LAN bridge between other offices
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MikroTik
From AP to the backbone
 Backup Links / Failover
 OSPF
 Tunnels over non-OSPF networks to OSPF
backbone networks
 Increasing throughput
 Aggregation of Interfaces multi-path routing
 PPTP tunnel compression
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MikroTik
From AP to the backbone (cont)
 Types of backbone connections
 additional point to point wireless 2.4GHz interfaces
using non-overlapping frequency or 5.8GHz
 licensed frequency microwave systems
 DSL connection from Telco
 Lease line from Telco using v.35 HDLC or E1/T1
interface in AP
 Use of HomePNA 14Mb/s interface up to 1.3km with
one twisted pair
 Use of SDSL up to 2.3Mb/s and 5km (speed
decreases with distance)
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Bandwith shaping
 problems when there is no shaping
 users get high speed local services on a
"luck" basis
 high paying users may get low quality service
when bandwidth is not managed
 backbones to wireless may get overloaded
 basic description of queues and function
 where to put queues
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Bandwith shaping (cont)
 simple queue and complex queue
configuration
 boss at client site wants better quality for
himself
 webserver and mail server may be specifically
shaped based on usage
 varied IP subnets may be put into one group
with a certain allocation
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Bandwith shaping (cont)
 scripting may be used to change the
bandwidth speed settings
 for a day speed and night speed
 tunnels linking enterprise networks may be
shaped and charged according to speed
 for example, a VPN tunnel with ethernet
bridging between a company warehouse
LAN and main office LAN
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Bandwith shaping (cont)
 DEMO CONFIGURATION AREA ON
ROUTER FOR SHAPING
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Interference and
antenna co-location
 2.4GHz frequencies (three non-overlapping)
 omni versus sectoral
 building top antenna co-location
 plan with barriers between antenna that have an
overlapping frequency
 example, concrete structure such as elevator gear
box houses
 mount on sides of building one floor or more below
roof top so that there is concrete separating the
antennas
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Interference and
antenna co-location (cont)
 2.4GHz frequencies (three nonoverlapping)
 omni versus sectoral
 Reflections (plus and minus)
 Signal may be reflected off another object to
make a connection when there is no line of
sight
 Reflections may cause a direct signal to be
cancelled
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Interference and
antenna co-location (cont)
 Interference may be mistaken for cabling
problems
 Cable is too long (10m or less is suggested
for client site – though locations close (less
than 2km) to the AP may have very long cable
 Water may have gotten into the strands of the
cable (cable must be replaced)
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Interference and
antenna co-location (cont)
 Grounding may be incorrect (if you see
small sparks when connecting cables)
 Radio cable may be located to some high
voltage lines that can cause interference
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Interference and
antenna co-location (cont)
 change polarity of overlapping frequency
antennas for a 20dB drop
 bandwidth test when installing antennas
 small movements of the mount location may
make giant differences
 using antenna diversity
 radio power and amplifiers
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Sample system design
 Situation proposed by audience
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