CSC2231 Review of Chord DNS

This paper implements DNS on the top of Chord to achieve self organization
and the easy of management compared with legacy DNS. Although Chord DNS
shows longer latency than legacy DNS, this papers provides an insightful
discussion about the pros and cons of p2p DNS.

Since Chord DNS does not exploit aggressive replication strategy used by
CoDoNS, its lookup latency is worse than the legacy DNS. Its average
lookup time is increased with the number of nodes in the system, but
legacy DNS lookup time is increased with the level of delegation. The
former could be much longer than the latter. Although this problem can be
alleviated by aggressive replication, the increase of replicas leads to
more overhead of consistency maintenance.

As CoDoNS, Chord DNS cannot provide full functionality of legacy DNS. It
simply considers name service as a query to its corresponding pair (domain
name, server IP addresses). However, a legacy DNS server can be
independently configured to only reply some specified clients; it can hide
internal domain to the outside; and it can provide dynamic domain name
resolution that enables CDN to select servers in network proximity and
load distribution. The authors argue that these functions should be
implemented by clients instead of servers, but this point seems
unrealistic.

Chord DNS claims they can provide good load balancing. But it cannot
effectively deal with load imbalance in a heterogeneous network, which is
inherited from DHT. Actually, load balancing issue is not very serious in
legacy DNS, which alleviates this problem by using anycast to reduce the
load of root servers.

In sum, we lack the incentives to use P2P DNS. Although its ease of
configuration outperforms legacy DNS, P2P DNS loses the flexibility of
independent control or dynamic resolution of legacy DNS. From the aspect of
economy, the difficulties of DNS configuration provide many jobs positions
as DNS administrators, and thus people may be not willing to transfer to
P2P DNS. Maybe P2P DNS will first work as a cache of legacy DNS in reality.
Received on Thu Nov 10 2005 - 10:16:25 EST