aglobalnameservicefor...

A Global Name Service for a Highly Mobile Internetwork

Abhigyan Sharma, Xiaozheng Tie, Hardeep Uppal, Arun Venkataramani, David Westbrook, Aditya Yadav

School of Computer Science University of Massachuse@s Amherst

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UNIVERSITY OF MASSACHUSETTS AMHERST • School of Computer Science

Mobile arrived, but Internet unmoved

§  UnidirecBonal communicaBon iniBaBon

§  Redundant app-‐specific mobility support

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Cleaner separaBon of locaBon and idenBty commonly advocated wisdom

?

Alice’s phone NoBficaBon systems VoIP/messaging Cloud storage

Bob

Alice

§  Ungraceful disrupBons


But DNS does separate idenFty / locaFon

§  Challenge: scaling to handle update cost of frequent mobility while returning up-‐to-‐date values •  Example: 10B devices, 100 addresses/day ≈ 1M updates/sec •  DNS update propagaBon can takes hours or days today!

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Domain names IP addresses

+ connecBon migraBon techniques


Scalable global name service (GNS)

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Goal: A massively scalable, logically centralized GNS to enable secure, name-‐based communicaFon with

flexible endpoint principals with arbitrary (fixed) names despite high mobility.

Global name service (GNS) interface device service content group of names

f0:56:81:c1:c0:eb node1.cs.umass.edu dropbox.com ne_lix.com/<object> devices in [lat,long,radius]


Outline

§ Poor intrinsic support for mobility today § Case for a next-‐generaFon GNS § Auspice GNS design §  ImplementaBon and evaluaBon § Related work, open issues, summary

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GNS criFcal to handle mobility

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Global name service

Alice

IP1

IP2 IP3

IP4

IP5

Bob

IP6

IP7

Alice’s a

ddress? Pre-‐lookup mobility

Connect-‐Bme mobility

Individual mobility

Simultaneous mobility

Pre-‐lookup mobility

GNS criBcal or can significantly benefit mobility handling in any network architecture


DNS limitaFons

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DNS

cache Load α 1/TTL Latency α 1/TTL

Mobility Mobility

Passive caching

StaBc placement

Hierarchical names

AuthoritaBve name-‐server ns.xyz.net

node1.xyz.net

.

com edu net

yahoo cnn umass

cs ece

FederaBon

DNSSEC key chain

Single root of trust

“JohnSmith2178@Amherst”!“Living room chandelier”!“Taxis near Times Square”!


Outline

§ Poor intrinsic support for mobility today § Case for a next-‐generaBon GNS § Auspice GNS design §  ImplementaBon and evaluaBon § Related work, open issues, summary

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GNS: Decoupling cerFficaFon and resoluFon

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Nam

e: “Alice’s ph

one”

TLD name services

Auth. name services

Root name service (ICANN, US. Dept. of Commerce)

CerFficate search services

GUID=X, GN

S=Auspice Domain name system Global name system

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3

4

4 1

0 Local name services

1

Local name services

2 Name cerFficaFon services

Managed DNS services

Auspice-‐like global name services


Resource cost

Name lookup latency

Consistent hashing with (staBc) k-‐replicaBon

Auspice

Resource limit

AcFve replicaFon cost-‐benefit tradeoff

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Replicate-‐at-‐all-‐locaBons

Update cost for name i α (#replicasi) x (update_ratei)

Lookup latency for name i ?


Demand-‐aware acFve replicaFon

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NS1

NS2

NS3

NS4

NS5

NS6

NS7

NS8 NS10 NS9

NS11

i

i

i

§  #replicas of name i α (read_ratei) / (update_ratei)

i i

i

j

j

j

Geolocality-‐aware Load-‐aware j j j


Placement reconfiguraFon engine

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NS1

NS2

NS3

NS4

NS5

NS6

NS7

NS8 NS10 NS9

NS11

i i

i j

j

j

NS3 NS7 NS2

NS4

NS9

NS1

NS5 NS8

NS10

NS11

i

i

i

i = replica controller for name i i = name record for name i name i

Demand geo-‐distribuBon

i i

Consistent hashing based placement control plane

Planned demand-‐aware placement for data plane


Outline

§ Poor intrinsic support for mobility today § Case for a next-‐generaBon GNS § Auspice GNS design §  ImplementaFon and evaluaFon § Related work, open issues, summary

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ImplementaFon §  Geo-‐distributed key-‐value store

§  Name cerBficaBon service

§  msocket user-‐level socket library with Auspice integraBon

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GUID: { !{IPs: [123.45.67.89, 98.76.54.321]},!{geoloc:[lat, long]},!{TE_prefs: [“prefer WiFi”,…]},!{ACL: {whitelist: […]}},!…!}!

Human-‐readable name: [email protected]:phone GUID: 21EC2020-‐3AEA-‐4069-‐A2DD-‐08002B30309D

MSocket socket = new MSocket([email protected]:phone);!MServerSocket socket = new MServerSocket(8080);!


0

50

100

150

200

250

300

48K 96K 144K 192K

Look

up la

tenc

y (m

s)

Load (in req/sec, reads = 2 * writes)

9x

5.7x

Replicate-at-all-locationsRandom-K

DHT+Popularity (Codons)Auspice

Placement schemes comparison

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Auspice gives close to best throughput and up to 9x lower latency than DHT+Popularity

Testbed: 16 server cluster emulaBng with 80 NS an 80 local NS Workload: 90% mobile names (geolocality 0.75), 10% service names


Managed DNS comparison

16

0

30

60

90

120

150

180

210

240

Look

up la

tenc

y (m

s)

Aus

pice

(5 re

plic

a)

Au

spic

e(1

0 re

plic

a)

Au

spic

e(1

5 re

plic

a)

Ultr

a D

NS

(16

repl

icas

)

One-‐third replicaBon cost, similar latency

60% less latency, similar cost

Auspice reduces cost/latency over today’s managed DNS

Ultra DNS (16 replicas) vs. Auspice 5/10/15 replicas out of 80 locaBons


§  Classical name services [Grapevine/ClearingHouse] used sta'c replicaBon •  Context-‐based names like Lampson’s “descripBve names”

§  DHT-‐based DNS designs [CoDoNS] ensure load balance, oblivious to demand geo-‐locality •  Locality-‐aware DHTs [SkipNet] (staBcally) place content close to origin, not near regions of its (dynamic) demand

§  Modern KV data stores support staBc geo-‐replicaBon [Cassandra] or manually-‐configured policy [Spanner]

Related work

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“the XEROX system [Grapevine] was then … the most sophisticated name service in existence, but it was not clear that its heavy use of replication, light use of caching ... were appropriate”

msocket.bind([lat, long, radius])!

msocket.send(msg)!msg msg msg msg msg


Auspice GNS summary Enables secure, name-‐based communicaBon

•  arbitrary name/locaBon representaBon •  flexible endpoint principals •  handles all types of mobility

§  Key differences from DNS for today’s Internet •  federaBon decoupling cerBficaBon and resoluBon •  acBve replicaBon •  demand-‐aware placement

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Get your GUID at: http://gns.name!

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