Report for 21508

Name

COMCAST-21508 - Comcast Cable Communications, LLC, US

AS Adjacency Report

In the context of this report "Upstream" indicates that there is an adjacent AS that lines between the BGP table collection point (in this case at AS6447) and the specified AS. Similarly, "Downstream" refers to an adjacent AS that lies beyond the specified AS. This upstream / downstream categorisation is strictly a description relative topology, and should not be confused with provider / customer / peer inter-AS relationships.

21508 COMCAST-21508, US

  Adjacency:    43  Upstream:     1  Downstream:    42
  Upstream Adjacent AS list
    AS7922          COMCAST-7922, US
  Downstream Adjacent AS list
    AS54391         CRUTCHFIELD, US
    AS11679         STIHL-204-124-67, US
    AS10794         BANKAMERICA, US
    AS27341         GFNET-AS01, US
    AS23209         VHDA20011260123220, US
    AS22274         SMP-VIR, US
    AS17381         AS-WSI-ECOM-WEST, US
    AS395527        -Reserved AS-, ZZ
    AS397190        WSP-DIGITAL, US
    AS396452        LOUDOUN-WATER, US
    AS399232        SETON-HOME, US
    AS399607        LCPS-VA, US
    AS46643         VIRGINIA-COLLEGE-SAVINGS-PLAN, US
    AS62971         COUNTY-OF-CHESTERFIELD-VA, US
    AS30299         THE-MARTIN-AGENCY-HQ, US
    AS393591        GAMEWOODTECHNOLOGYGROUP, US
    AS393613        VACU-ASN-1, US
    AS394058        TELOSC-ASH, US
    AS397483        -Reserved AS-, ZZ
    AS19404         QUEST, US
    AS36364         MHSNET, US
    AS63468         INFINITTNA, US
    AS11739         CHIRISA-TECHNOLOGY-PARKS-01, US
    AS14583         VITA-VSP-1, US
    AS19923         SHENANDOAH-UNIV, US
    AS32540         HP-HOOD, US
    AS2134          GSVNET-AS GS Virtual Network Produban, ES
    AS18773         HENRICO-AS, US
    AS15297         EPLUS-ASN, US
    AS15173         NEWMA-11, US
    AS36244         SVEC, US
    AS395772        AHC-AS, US
    AS396083        ARVUS-160-84, US
    AS399099        PCPS-ASN, US
    AS399938        BHE-TRANSIT, US
    AS397039        WORLDSTRIDES, US
    AS400114        APOG-RBC, US
    AS54219         SCHAWK-INC, US
    AS40641         MGWTEL, US
    AS54883         CORVA, US
    AS36040         YOUTUBE, US
    AS13335         CLOUDFLARENET, US

Announced Prefixes

Rank  AS       Type    Originate Addr Space  (pfx)   Transit Addr space  (pfx)  Description
2990  AS21508        ORG+TRN Originate:      71424 /15.88  Transit:      75264 /15.80 COMCAST-21508, US

Aggregation Suggestions

        Filter: Aggregates, Specifics

This report does not take into account conditions local to each origin AS in terms of policy or traffic engineering requirements, so this is an approximate guideline as to aggregation possibilities.

 Rank AS            AS Name                                      Current  Wthdw  Aggte  Annce Redctn       %
35996 AS21508       COMCAST-21508, US                                 18      0      0     18      0   0.00%


  Prefix               AS Path                              Aggregation Suggestion
  50.204.101.0/24      6939 7922 21508        
  50.205.217.0/24      3257 7922 21508        
  50.216.229.0/24      3257 7922 21508        
  50.217.1.0/24        3257 7922 21508        
  50.217.207.0/24      6939 7922 21508        
  50.218.47.0/24       3257 7922 21508        
  50.219.12.0/22       6939 7922 21508        
  50.228.113.0/24      3257 7922 21508        
  50.229.113.0/24      6939 7922 21508        
  50.229.114.0/24      6939 7922 21508        
  50.235.34.0/24       3257 7922 21508        
  141.104.0.0/16       6939 7922 21508        
  157.240.147.0/24     3257 7922 21508        
  157.240.148.0/24     6939 7922 21508        
  173.242.174.0/24     3257 7922 21508        
  198.90.112.0/22      6939 7922 21508        
  204.194.47.0/24      3257 7922 21508        
  205.223.19.0/24      3257 7922 21508        

Advertisements that are fragments of the original RIR allocation (more specifics) originated by this AS.

AS21508   24 More Specifics   26 Total Advertisements   COMCAST-21508, US
    50.204.101.0/24               50.128.0.0/9
    50.205.217.0/24               50.128.0.0/9
    50.216.229.0/24               50.128.0.0/9
    50.217.1.0/24                 50.128.0.0/9
    50.217.207.0/24               50.128.0.0/9
    50.218.47.0/24                50.128.0.0/9
    50.219.12.0/22                50.128.0.0/9
    50.219.193.0/24               50.128.0.0/9
    50.220.111.0/24               50.128.0.0/9
    50.227.24.0/24                50.128.0.0/9
    50.228.113.0/24               50.128.0.0/9
    50.229.113.0/24               50.128.0.0/9
    50.229.114.0/24               50.128.0.0/9
    50.229.232.0/24               50.128.0.0/9
    50.229.233.0/24               50.128.0.0/9
    50.234.62.0/23                50.128.0.0/9
    50.235.34.0/24                50.128.0.0/9
    50.237.96.0/24                50.128.0.0/9
    157.240.147.0/24              157.240.0.0/16
    157.240.148.0/24              157.240.0.0/16
    173.242.174.0/24              173.242.160.0/20
    198.90.112.0/22               198.90.96.0/19
    204.194.47.0/24               204.194.40.0/21
    205.223.19.0/24               205.223.16.0/20
    50.219.222.0/24               50.128.0.0/9
    50.219.229.0/24               50.128.0.0/9

Prefixes added and withdrawn by this origin AS in the past 7 days.

    + 50.234.62.0/23              Announced
    - 50.219.222.0/24             Withdrawn
    - 50.219.229.0/24             Withdrawn

Whois Entry

whois: 402551

IANA has recorded AS21508 as originally allocated by 
/usr/bin/whois -h jwhois.apnic.netr "AS21508\n             
             #
             # ARIN WHOIS data and services are subject to the Terms of Use
             # available at: https://www.arin.net/resources/registry/whois/tou/
             #
             # If you see inaccuracies in the results, please report at
             # https://www.arin.net/resources/registry/whois/inaccuracy_reporting/
             #
             # Copyright 1997-2026, American Registry for Internet Numbers, Ltd.
             #
             
             
             ASNumber:       21508
             ASName:         COMCAST-21508
             ASHandle:       AS21508
             RegDate:        2001-05-16
             Updated:        2021-01-25
             Ref:            https://rdap.arin.net/registry/autnum/21508
             
             
             
             OrgName:        Comcast Cable Communications, LLC
             OrgId:          CCCS
             Address:        1800 Bishops Gate Blvd
             City:           Mt Laurel
             StateProv:      NJ
             PostalCode:     08054
             Country:        US
             RegDate:        2001-09-18
             Updated:        2020-11-18
             Ref:            https://rdap.arin.net/registry/entity/CCCS
             
             
             OrgTechHandle: IC161-ARIN
             OrgTechName:   Comcast Cable Communications Inc
             OrgTechPhone:  +1-856-792-2300 
             OrgTechEmail:  CNIPEO-Ip-registration@cable.comcast.com
             OrgTechRef:    https://rdap.arin.net/registry/entity/IC161-ARIN
             
             OrgRoutingHandle: ROUTI25-ARIN
             OrgRoutingName:   Routing
             OrgRoutingPhone:  +1-856-792-2300 
             OrgRoutingEmail:  routing@comcast.com
             OrgRoutingRef:    https://rdap.arin.net/registry/entity/ROUTI25-ARIN
             
             OrgAbuseHandle: NAPO-ARIN
             OrgAbuseName:   Network Abuse and Policy Observance
             OrgAbusePhone:  +1-888-565-4329 
             OrgAbuseEmail:  abuse@comcast.net
             OrgAbuseRef:    https://rdap.arin.net/registry/entity/NAPO-ARIN
             
             
             #
             # ARIN WHOIS data and services are subject to the Terms of Use
             # available at: https://www.arin.net/resources/registry/whois/tou/
             #
             # If you see inaccuracies in the results, please report at
             # https://www.arin.net/resources/registry/whois/inaccuracy_reporting/
             #
             # Copyright 1997-2026, American Registry for Internet Numbers, Ltd.
             #