<< to the main Ivip page.
This is a 995 word version for the RRG discussion and selection process.
Ivip Summary Robin Whittle 2009-12-18
The 2100 word http://www.firstpr.com.au/ip/ivip/Ivip-RRG.html has more
explanation and qualifications.
Ivip (pr. eye-vip, est. 2007-06-15) is a core-edge separation scheme
for IPv4 and IPv6. It provides multihoming, portability of address
space and inbound traffic engineering for end-user networks of all
sizes and types, including those of corporations, SOHO and mobile
Ivip meets all the constraints imposed by the need for widespread
voluntary adoption .
Ivip's global fast-push mapping distribution network is structured
like a cross-linked multicast tree. This pushes all mapping changes
to full database query servers (QSDs) within ISPs and end-user
networks which have ITRs. Each mapping change is sent to all QSDs
within a few seconds.
ITRs gain mapping information from these local QSDs within a few tens
of milliseconds. QSDs notify ITRs of changed mapping with similarly
low latency. ITRs tunnel all traffic packets to the correct ETR
without significant delay.
Ivip's mapping consists of a single ETR address for each range of
mapped address space. Ivip ITRs do not need to test reachability to
ETRs because the mapping is changed in real-time to that of the
End-user networks control the mapping, typically by contracting a
specialized company to monitor the reachability of their ETRs and
change the mapping to achieve multihoming and/or TE. So the
mechanisms which control ITR tunneling are controlled by the end-user
networks in real-time and are completely separate from the core-edge
separation scheme itself.
ITRs can be implemented in dedicated servers or hardware-based
routers. The ITR function can also be integrated into sending hosts.
ETRs are relatively simple and only communicate with ITRs rarely -
for Path MTU management with longer packets.
Ivip-mapped ranges of end-user address space need not be subnets.
They can be of any length, in units of IPv4 addresses or IPv6 /64s.
Compared to conventional unscalable BGP techniques, and to the use of
core-edge separation architectures with non-real-time mapping
systems, end-user networks will be able to achieve more flexible and
responsive inbound TE. If inbound traffic is split into several
streams, each to addresses in different mapped ranges, then real-time
mapping changes can be used to steer the streams between multiple
ETRs at multiple ISPs.
Open ITRs in the DFZ (OITRDs, similar to LISP's PTRs) tunnel packets
sent by hosts in networks which lack ITRs. So multihoming,
portability and TE benefits apply to all traffic.
ITRs request mapping either directly from a local QSD or via one or
more layers of caching query servers (QSCs) which in turn request it
from a local QSD. QSCs are optional but generally desirable since
they reduce the query load on QSDs.
ETRs may be in ISP or end-user networks. IP-in-IP encapsulation is
used, so there is no UDP or any other header. PMTUD (Path MTU
Discovery) management with minimal complexity and overhead will
handle the problems caused by encapsulation, and adapt smoothly to
jumboframe paths becoming available in the DFZ. The outer header's
source address is that of the sending host - which enables existing
ISP BR filtering of source addresses to be extended to encapsulated
traffic packets by the simple mechanism of the ETR dropping packets
whose inner and outer source address do not match.
The TTR approach to mobility  is applicable to all core-edge
separation techniques and provides scalable IPv4 and IPv6 mobility
in which the MN keeps its own mapped IP address(es) no matter how
or where it is physically connected, including behind one or more
layers of NAT.
Path-lengths are typically optimal or close to optimal and the MN
communicates normally with all other non-mobile hosts (no stack or
app changes), and of course other MNs. Mapping changes are only
needed when the MN uses a new TTR, which would typically be if the
MN moved more than 1000km. Mapping changes are not required when
the MN changes its physical address(es).
Modified Header Forwarding
Separate schemes for IPv4 and IPv6 enable tunneling from ITR to
ETR without encapsulation. This will remove the encapsulation
overhead and PMTUD problems. Both approaches involve modifying
all routers between the ITR and ETR to accept a modified form of
the IP header. These schemes require new FIB/RIB functionality in
DFZ and some other routers but do not alter the BGP functions of
Amenable to widespread voluntary adoption due to no need for host
changes, complete support for packets sent from non-upgraded networks
and no significant degradation in performance.
Modular separation of the control of ITR tunneling behavior from the
ITRs and the core-edge separation scheme itself: end-user networks
control mapping in any way they like, in real-time.
A small fee per mapping change deters frivolous changes and helps pay
for pushing the mapping data to all QSDs. End-user networks who make
frequent mapping changes for inbound TE, should find these fees
attractive considering how it improves their ability to utilize the
bandwidth of multiple ISP links.
End-user networks will typically pay the cost of OITRD forwarding to
their networks. This provides a business model for OITRD deployment
and avoids unfair distribution of costs.
Existing source address filtering arrangements at BRs of ISPs and
end-user networks are prohibitively expensive to implement directly in
ETRs, but with the outer header's source address being the same as the
sending host's address, Ivip ETRs inexpensively enforce BR filtering on
QSDs receive all mapping changes and store a complete copy of the
mapping database. However, a worst case scenario is 10 billion IPv6
mappings, each of 32 bytes, which fits on a consumer hard drive today
and should fit in server DRAM by the time such adoption is reached.
The maximum number of non-mobile networks requiring multihoming etc. is
likely to be ~10M, so most of the 10B mappings would be for mobile
devices. However, TTR mobility does not involve frequent mapping
changes since most MNs only rarely move more than 1000km.