Transcript Comcast

IPv6 @ Comcast
Managing 100+ Million
IP Addresses
2006-02-06
Alain Durand
Advanced Engineering
Director – IPv6 Architect
[email protected]
Agenda
• Comcast needs for IPv6
• Comcast plans for IPv6
• The IPv6 (Cable) Network at Home
2
Comcast needs for IPv6
3
Simplistic View of Comcast IP problem
20 Million video customer
2.5 set-top box per customer
2 IP addresses per set-top box
---------------------------------------Total: 100 Millions IP address
And we have not yet talked about High Speed Data…
nor Comcast Digital Voice…
nor merger/acquisition…
4
Comcast Specific Needs
• The extra large address space we need is for management
(a.k.a. control plane) of Cable Modems, eMTA and Set-Top boxes. This is not
for customer PC-type devices (data plane). This would require a separate
allocation.
• This address space is for internal consumption only, i.e. it is not seen from
outside Comcast.
• Until recently, Comcast was using Net 10 (RFC1918) for managing the
modems. That space has been exhausted.
• Comcast recently was allocated the largest part of Net 73 and is currently
renumbering cable modems in that space.
• In the control plane, all devices need to be remotely managed,
so NAT isn’t going to help us…
• IPv6 is the clear solution for us
• However, even we are starting now, the move to IPv6 is not going to happen
overnight
5
Comcast Needs about 100 Million IP Addresses
(in the next coming years)
90
IPv4
IPv6
Comcast IP Demand (in million)
80
Contingency Plans
70
60
50
40
New
30
Old
20
10
0
Contingency plans have already
started with the use of public
address space (Net73)
6
Contingency plans end with
the full support of IPv6 within
Comcast network.
Contingency Plans: Buying Time to Deploy IPv6
or how to Get 100 Million IPv4 Addresses (and more)?
Plan
Public Address Space
“Dark” Space
Federalization
Description
Go to ARIN and ask for address space
every time we can justify it in
accordance to their policies.
Use already allocated, non-globally
routed, public IPv4 address space.
Those blocks need to be carefully
selected to avoid potential conflicts
(e.g. Net 45 from Interop).
Subdivide the network into several
independently managed domains
(e.g. division boundaries).
Impact
Minimal.
Operationally minimal unless a
conflict arises.
Loss of global visibility in the
network.
Need to redesign the network.
7
Comcast plans for IPv6
8
Comcast IPv6 Strategy
1 - Plan for IPv6 deployment NOW
2 – Deploy IPv6 initially for the management and operation
of the customer devices we manage:
- Docsis CM
- Set Top boxes, PacketCable MTA,…
3 - Be ready to offer to customers services that take advantage of IPv6
9
IPv6 Migration – Guiding Principles
• The migration to IPv6 project has the following principles:
– Deploying IPv6 must be minimally disruptive to the operations
of existing networks and devices
– IPv6 must be included in the roadmap of next generation
equipment and devices
– Comcast operations, infrastructure and systems must become
ready to support IPv6-enabled devices
– IPv6 will slowly penetrate Comcast DNA
10
IPv6 Deployment: Principles and Approach
• Primary objective is to deploy IPv6
for the IP address of the CM & STB.
• Architecture: dual-stack at the core,
v6-only at the edges
2005
Backbone
– Deployment consists of co-existence and dual
stack in the core networks (Backbone, CRAN,
Back Office), and IPv6-only at the edge (CM,
STB, MTA…) for new devices.
• Deployment approach:
from the core to the edges
– Backbone -> Regional Networks
->CMTS -> Devices
– This is an incremental deployment; existing
deployments will be unaffected in the beginning.
• Follow same operational model
as with IPv4
11
Systems
Regional Networks
CMTS
CM
CM
CM
CM
CM
CM
PC
PC
PC
STB
STB
STB
New
Legacy
New
IPv6 Certification
• Basic IPv4 –compliance is somehow taken for granted today on most
equipment
– IP level component testing is thus limited
• IPv6 is still a very new technology
• The level of maturity of implementations varies greatly among
vendors
– Some have had an IPv6 story for about 10 years
• Even those implementations have some features that are not fully baked
– Others have still nothing and are going to rush to buy a 3rd party stack and
integrate it on their products
• The bar for acceptance of IPv6 product has to be set higher than for
IPv4
– Formal IPv6 requirement list at purchase time
– IPv6 conformance certification to accept products
12
IPv6 Training
• IPv6 is still a very new technology
• Most engineers have heard about it but don’t know much about it
– Fear factor is important to control
• We can expect new hires to have 2-4 years of IPv4 experience, but
can’t expect anything about IPv6
• Initial and continuous training is critical
– Academic style training presentation
– Web-based classes
– Hands-on exprience
13
IPv6 Challenge: Aligning Several Timelines
• IPv6 cable modem availability
• Dual Stack Network
• IPv6-aware CMTS
• Provisioning and monitoring system made IPv6 aware
• Video / Voice systems
• Retail Market (Consumer Electronic)
– Home Gateways
– Video (e.g. TV with embedded cable modem)
14
Modems and Mode of Operation
• New modems will be IPv6 ready
• When configured on IPv4-only CMTS, they will be provisioned with IPv4
• When configured on IPv6-enable CMTS, they will be provisioned with IPv6
• Modems will never have both IPv4 & IPv6 addresses at the same time
– If we could give both an IPv4 and an IPv6 address at the same time,
we will not need IPv6 in the first place!
Cable Modem
TCP4
IPv4
NIC driver
15
Cable Modem
TCP6
or
IPv6
NIC driver
depending on an
L2 config message
Dual Stack Network
• Routers can exchange routes and forward packets in a “dual-stack”
mode on the same physical links.
R
R
R
16
Routing can be integrated
(e.g. BGP, IS-IS) for both
IPv4 and IPv6 or can run
“ship in the night”
(e.g. OSPFv2 & OSPFv3)
Network Challenges
• Monitoring routers
– IPv6 MIBs and software to monitor them
• Choice of IGP
– Comcast run OSPFv2 for IPv4
– Should we run OSPFv3 for IPv6 “Ship in the Night” or migrate the whole thing to
run “integrated” with IS-IS?
– What are the failure mode for end to end dual stack applications when the routing
for either IPv4 or IPv6 fails?
– Impact on MTR
– Impact of BFD
• Integrating IPv4 & IPv6 security
• Integrating IPv4 & IPv6 QoS
17
Provisioning, Monitoring, Back-Office
• Mostly a software upgrade problem
– Not unlike the Y2K problem
– Fields need to be bigger in database & web scripts
• Should system “X” be upgraded for IPv6?
– Transport questions
• Does system “X” communicate with devices that are potentially IPv6-only (e.g. CM)?
– Payload questions
• Does system “X” manipulate IP data (store, input or display)?
• Could those data be IPv6?
• Comcast case
– About 100 “systems”
– 10 need major updates for transport
– 30 need minor updates for display/storage
18
IPv4 Management of Dual Stack Routers
• Routers can still be configured using
IPv4 management systems.
R
R
R
R
Router
Management
System
• However router management systems need to be modified
to display/input/store IPv6 related data.
19
IPv6 Management of Cable Modems
• IPv6-only CM are configured using IPv6 management/provisioning
systems over a dual-stack network.
CMTS
CM
20
R
R
R
CM
Management/
Provisioning
System
Back Office Management of Cable Modems
• Back-office systems do not communicate directly with the CM,
thus their network transport can remain IPv4.
• However back office systems may need
to be modified to display/input/store
IPv6 related data (CM IPv6 addresses)
CMTS
CM
21
R
R
Router
Management
System
R
CM
Management/
Provisioning
System
Back-office
Back-office
Back-office
DB
(optional) IPv6 Management of IPv4 Cable Modems
• IPv4-only CM are configured using IPv6 management systems
via a translator.
Global IPv6 prefix:
2001:db8:aaaa:aaaa::/64
(assign to the CMTS)
CMTS
R
Translator
Local IPv4 address:
10.1.2.3
(allocated by
the CMTS)
CM
R
R
CM
Management/
Provisioning
System
Global IPv6 address:
2001:db8:aaaa:aaaa:0:0:0a01:0203
to uniquely identify the modem
22
The IPv6 (Cable) Network at Home
23
Key Elements of the Home Network of the Future
• Large number of IP devices, not all being computers
– Dual stack networks (v4/v6)
• Multiple links with different characteristics:
– Wired/wireless, different speeds, multi-cast support,…
• New network layer demand
– Mobility, Security, QoS
• Additional services
– Home automation, video communications
– Network Storage,…
• Very limited management skills
• Evolution, not revolution
24
How to Build it?
• IPv6 and Docsis 3.0 are the basic building blocs
– Address space
– Bandwidth
• DHCPv6 is the IP configuration method of choice for any device either
directly attached to the cable or bridged to it.
– Devices behind a home router may use stateless auto-configuration
• The home networks of the future require smart gateway
– Not just access routers, but include all kinds of features/services
25
Case Studies
• The single PC at home
• The IP Set Top Box with an embedded CM
• The combined MTA + PC modem
• The home network with a home gateway
26
Case Study 1: the Single bridged PC at Home
DHCPv6
DHCPv6, CM
CMTS
27
DHCPv6
CM
PC
Case Study 2: the IP Set Top Box with eCM
DHCPv6
DHCPv6, CM
CMTS
CM STB
DHCPv6, STB
28
Case Study 3: combined MTA + PC modem
DHCPv6
DHCPv6, CM
CMTS
CM
DHCPv6, MTA
29
PC
CMCI
DHCPv6
MTA
Case Study 4: the Home Network
DHCPv6
PC1
DHCPv6
DHCPv6, CM
CMTS
CM
Gateway
PC2
DHCPv6 + PD
Stateless
Autoconf
30
PC3