Aggregate fragmented lists of IP subnets and CIDR blocks into optimized supernets to clean BGP routing tables.
Contiguous Block Breakdown & CIDRs
'. In BGP, the 'aggregate-address
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Invalid IPv6: too many segments
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RouteAggregation component file is being evaluated...
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10.1.0.0/24\n10.1.1.0/24\n10.1.2.0/24\n192.168.1.1 - 192.168.1.254\n2001:db8:abc:1::/64\n2001:db8:abc:2::/64\n2001:db8:abc:3::/64
10.10.1.0/24\n10.10.2.0/24\n10.10.3.0/24\n10.10.4.0/22\n172.16.5.10 - 172.16.5.20
2001:db8:aaaa:1::/64\n2001:db8:aaaa:2::/64\n2001:db8:aaaa:3::/64\n2001:db8:aaaa:4::/62
Invalid range separator '-' count
Invalid IPs in range or mismatched families
Invalid CIDR separator '/' count
Unrecognized format (use e.g. 10.0.0.0/24 or 10.0.0.1 - 10.0.0.5)
Aggregation calculation failed:
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Convert IP address ranges to CIDR notations and aggregate multiple subnet routing tables into consolidated summaries automatically. Supporting IPv4 and IPv6.
route aggregator, subnet aggregator, range to cidr, cidr converter, route summarization, supernet calculator
Consolidate your subnets and convert raw IP ranges into clean CIDR blocks.
Aggregate multiple subnets into optimized summary routes or convert arbitrary IP ranges into clean CIDR notations for IPv4 and IPv6.
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Example: 10.1.0.0/24 10.1.1.0/24 192.168.1.1 - 192.168.1.254 2001:db8::/64
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Aggregate multiple IP subnets into a single supernet route or convert non-contiguous IP ranges into precise lists of CIDR blocks.
OSPF Area Ranges, BGP aggregate-address, EIGRP summary-addresses, Cisco, Nokia, Juniper, Huawei, ECI
List of subnets or IP ranges, one per line (e.g. 192.168.1.0/24 or 10.0.0.1 - 10.0.0.250)
Consolidated list of CIDR subnets, utilization percentage efficiency, overall supernet prefix, and discard Null0 commands.
Always configure a blackhole/Null0 static route for the summary prefix to prevent routing loops for inactive destination IPs.
Group IP address plans into contiguous blocks during initial design to maximize summarization opportunities.
Align IPv6 aggregates to 4-bit nibble boundaries (/48, /52, /56, /64) for human readability.
Consolidating routing tables on core routers to reduce TCAM resource utilization.
Translating DHCP address ranges or firewall IP scopes into CIDR rules.
Defining OSPF area-range aggregates or BGP advertisements.
Routers always prefer the Longest Prefix Match (LPM) over a summary route.
A /22 supernet covers four adjacent /24 subnets. If some are unused, packets to them will follow the summary route.
Use this tool when designing routing protocol boundaries (like OSPF area boundaries or BGP network advertisement nodes) or when preparing firewall policies, security group rules, or cloud VPC routing configurations that do not support range-based IP filters.
IPv6 Nibble Boundary Summarization
While bitwise alignment works mathematically on any bit index for IPv6, it is highly recommended to summarize on nibble boundaries (multiples of 4 bits: /48, /52, /56, /60, /64). This matches the hexadecimal notation characters, keeping configuration files human-readable and maintaining easy diagnostics.
What is the difference between Supernetting and Subnetting?
Subnetting is the process of dividing a single large network block into smaller, separate networks (e.g., splitting a /24 into multiple /26s). Supernetting (summarization) is the reverse: combining multiple smaller, adjacent network blocks into a single larger prefix (e.g., combining four /24s into a single /22).
Why does the Range to CIDR converter output multiple subnets for some ranges?
Because CIDR prefixes must align with binary boundaries and represent sizes that are powers of two. If an IP range starts or ends on a non-power-of-two offset, the converter must break it down into smaller, aligned subnets to cover the range exactly without including extra IP addresses.
What is a Null0 route and why is it needed for summarization?
How does the router choose between a specific route and a summary route?
Routers use the Longest Prefix Match (LPM) rule. If a router has a specific route (e.g., 10.1.1.0/24) and a summary route (e.g., 10.1.0.0/22), it will always choose the more specific route (/24) for forwarding traffic to that network.
What happens if I try to summarize non-contiguous IP blocks?
You can mathematically summarize them, but the resulting supernet prefix will cover a much larger address space, including many IPs that you do not own or want to route. It is usually better to advertise them as separate prefixes or group them into contiguous blocks first.
What are the common routing protocol commands for summarization?
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Subnetting is the process of dividing a single large network block into smaller, separate networks (e.g., splitting a /24 into multiple /26s). Supernetting (summarization) is the reverse: combining multiple smaller, adjacent network blocks into a single larger prefix (e.g., combining four /24s into a single /22).
Because CIDR prefixes must align with binary boundaries and represent sizes that are powers of two. If an IP range starts or ends on a non-power-of-two offset, the converter must break it down into smaller, aligned subnets to cover the range exactly without including extra IP addresses.
A Null0 route is a static route that discards traffic. When you summarize a route, the router advertises reachability for the entire block, even if some IPs inside it are unassigned. A Null0 route is configured for the summary prefix so that packets sent to unassigned IPs are discarded instead of looping between the router and its default gateway.
Routers use the Longest Prefix Match (LPM) rule. If a router has a specific route (e.g., 10.1.1.0/24) and a summary route (e.g., 10.1.0.0/22), it will always choose the more specific route (/24) for forwarding traffic to that network.
You can mathematically summarize them, but the resulting supernet prefix will cover a much larger address space, including many IPs that you do not own or want to route. It is usually better to advertise them as separate prefixes or group them into contiguous blocks first.
Yes, this tool automatically detects the IP family of each input line. It separates them into IPv4 and IPv6 groups and calculates the respective summaries and range conversions independently.
In OSPF, summarization is configured at area boundaries using 'area
Yes! For IPv4, the tool compares the total number of IP addresses requested (summed from your input CIDRs/ranges) against the total address capacity of the generated overall supernet. This gives you a clear percentage efficiency rate.