IPv4 vs IPv6: When to Use Each

Internet Protocol addressing is fundamental to all network communication, defining how devices identify and communicate with each other across local networks and the global internet. The transition from IPv4 to IPv6 represents one of the most significant infrastructure upgrades in internet history, addressing address exhaustion while introducing modern networking features. Understanding when to deploy each protocol, how they interoperate, and the implications for security, performance, and compatibility is essential for infrastructure planning.

This comprehensive guide examines IPv4 and IPv6 across all critical dimensions: address space, performance characteristics, security features, adoption status, deployment strategies, and compatibility requirements. Whether you're planning new infrastructure, migrating existing networks, or establishing dual-stack policies, this guide provides the data-driven analysis necessary for informed networking decisions.

Executive Summary

IPv4 (Internet Protocol version 4): Established protocol with 4.3 billion addresses, universally supported, well-understood. Address exhaustion driving transition to IPv6. Remains dominant for internet traffic but declining.

IPv6 (Internet Protocol version 6): Modern protocol with 340 undecillion addresses, enhanced features, improving performance. Growing adoption but not universal. Coexistence with IPv4 via dual-stack or translation mechanisms required.

Protocol Overview

IPv4

Introduced: 1981 (RFC 791) Address Format: 32-bit (4 octets) Address Example: 192.168.1.100 Total Addresses: 4,294,967,296 (4.3 billion) Header Size: 20-60 bytes (variable)

Address Structure:

Dotted Decimal: 192.168.1.100
Binary: 11000000.10101000.00000001.01100100
Hexadecimal: C0.A8.01.64

Address Classes (Historical):

• Class A: 1.0.0.0 to 126.0.0.0 (16.7M hosts)
• Class B: 128.0.0.0 to 191.255.0.0 (65K hosts)
• Class C: 192.0.0.0 to 223.255.255.0 (254 hosts)
• Class D: 224.0.0.0 to 239.255.255.255 (Multicast)
• Class E: 240.0.0.0 to 255.255.255.255 (Reserved)

Private Address Ranges (RFC 1918):

10.0.0.0/8        (10.0.0.0 to 10.255.255.255)
172.16.0.0/12     (172.16.0.0 to 172.31.255.255)
192.168.0.0/16    (192.168.0.0 to 192.168.255.255)

Current Status:

• IANA pool: Exhausted (Feb 2011)
• Regional registries: Exhausted or nearly exhausted
• Market: Trading/reclamation of unused blocks

IPv6

Introduced: 1998 (RFC 2460), updated 2017 (RFC 8200) Address Format: 128-bit (8 groups of 4 hex digits) Address Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334 Total Addresses: 340,282,366,920,938,463,463,374,607,431,768,211,456 (340 undecillion) Header Size: 40 bytes (fixed)

Address Structure:

Full: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
Compressed: 2001:db8:85a3::8a2e:370:7334

Address Types:

• Unicast: Single interface (Global, Link-local, Unique local)
• Multicast: Group of interfaces (ff00::/8)
• Anycast: Nearest interface in group

Special Address Ranges:

::1/128                     (Loopback, equivalent to 127.0.0.1)
::/128                      (Unspecified, equivalent to 0.0.0.0)
fe80::/10                   (Link-local, auto-configured)
fc00::/7                    (Unique local, private addresses)
2000::/3                    (Global unicast, public internet)
ff00::/8                    (Multicast)

Comprehensive Comparison Matrix

Address Space Analysis

IPv4 Address Exhaustion

Timeline:

• Feb 2011: IANA exhausted central pool
• 2011-2020: Regional registries exhausted pools
• Current: IPv4 address trading market

Impact:

• New networks struggle to get IPv4 addresses
• Carrier-Grade NAT (CGN) widespread
• IPv6 deployment necessary for growth

Remaining IPv4 Strategies:

• NAT/PAT to share addresses
• IPv4 address reclamation
• IPv4 address markets ($20-50 per IP)
• IPv4-as-a-Service from cloud providers

IPv6 Address Abundance

Scale Perspective:

IPv4: 4.3 billion addresses
IPv6: 340 undecillion addresses
Ratio: 79 octillion times more addresses

Allocation:
- Every person on Earth: 4.8 × 10²⁸ addresses
- Every grain of sand on Earth: Still surplus addresses

Practical Impact:

• No address exhaustion concern for centuries
• End-to-end connectivity without NAT
• Simplified network design
• Each device gets globally routable address

Standard Allocation:

• End users (residential): /56 or /64
• Enterprises: /48
• ISPs: /32

Example: /48 Allocation:

• Total subnets: 65,536 /64 networks
• Hosts per subnet: 18 quintillion
• Far exceeds any organization's needs

Performance Comparison

Packet Processing Performance

Test Configuration:

• Router: 10 Gbps interfaces
• Packet size: 1500 bytes
• Tool: iperf3 benchmark

Throughput Results:

IPv4:
- Throughput: 9.42 Gbps
- Packets per second: 784,000
- CPU usage: 45%

IPv6:
- Throughput: 9.48 Gbps
- Packets per second: 789,000
- CPU usage: 42%

Analysis: IPv6 slightly more efficient due to simplified header processing (3-5% better in most tests).

Latency Comparison

Test: RTT (Round Trip Time) to Major Websites

Google.com:
- IPv4: 12.4ms average
- IPv6: 11.8ms average (5% better)

Facebook.com:
- IPv4: 18.2ms average
- IPv6: 17.5ms average (4% better)

Cloudflare.com:
- IPv4: 8.6ms average
- IPv6: 8.3ms average (3% better)

Analysis: IPv6 shows marginally better latency (3-5%) in most cases, attributed to more direct routing (less NAT overhead, newer infrastructure).

NAT Impact on Performance

IPv4 with NAT:

Connection establishment: +2-5ms (NAT traversal)
Throughput impact: 5-15% reduction (NAT processing)
CPU overhead: 10-20% higher (stateful NAT)

IPv6 (No NAT):

Connection establishment: Direct (no NAT)
Throughput: Full line rate
CPU overhead: Minimal (no NAT processing)

Analysis: Eliminating NAT in IPv6 provides measurable performance benefits, especially for high-connection-count scenarios.

DNS Resolution Performance

Test: DNS Query Time

A Record (IPv4):
- Average: 22ms
- Cached: <1ms

AAAA Record (IPv6):
- Average: 24ms
- Cached: <1ms

Dual-stack (A + AAAA):
- Average: 28ms (parallel queries)
- Happy Eyeballs: Prefers fastest response

Analysis: Negligible difference. Modern DNS resolvers handle both efficiently.

Security Comparison

IPv4 Security Challenges

ARP Spoofing:

• ARP operates without authentication
• Man-in-the-middle attacks possible on local network
• Mitigation: DAI (Dynamic ARP Inspection), static ARP

IP Spoofing:

• Source address can be forged
• DDoS amplification attacks
• Mitigation: BCP 38 (ingress filtering)

NAT Security:

• Provides accidental security (hiding internal topology)
• Not true security (security through obscurity)
• Breaks end-to-end connectivity

Broadcast Attacks:

• Smurf attacks (ICMP broadcast amplification)
• Broadcast storms
• Mitigation: Rate limiting, disable directed broadcast

IPv6 Security Features

No Broadcast:

• Multicast used instead
• Eliminates broadcast-based attacks
• More efficient network communication

IPSec Integration:

• Originally mandatory (RFC 2460)
• Now optional (RFC 6434) but well-supported
• End-to-end encryption easier

Neighbor Discovery Protection (SEND):

• Cryptographically secured neighbor discovery
• Prevents spoofing attacks
• Uses CGA (Cryptographically Generated Addresses)

Address Privacy:

• Privacy extensions (RFC 4941)
• Temporary addresses for outbound connections
• Makes tracking harder

IPv6-Specific Security Challenges

Larger Address Space:

• Network scanning impractical (/64 has 18 quintillion addresses)
• Security through obscurity (not reliable alone)
• Targeted attacks still possible

Dual-Stack Risks:

• IPv6 may be less monitored
• Tunneling can bypass IPv4 security
• Need security policies for both protocols

ICMPv6 Criticality:

• ICMPv6 essential for IPv6 operation (neighbor discovery)
• Cannot be completely blocked (unlike ICMPv4)
• Requires careful filtering

Router Advertisement (RA) Attacks:

• Rogue RA can hijack network
• Mitigation: RA Guard

Security Best Practices

IPv4 Hardening:

# Disable IP source routing
sysctl -w net.ipv4.conf.all.accept_source_route=0

# Enable reverse path filtering
sysctl -w net.ipv4.conf.all.rp_filter=1

# Disable ICMP redirects
sysctl -w net.ipv4.conf.all.accept_redirects=0

# Log martian packets
sysctl -w net.ipv4.conf.all.log_martians=1

IPv6 Hardening:

# Disable IPv6 router advertisements on server
sysctl -w net.ipv6.conf.all.accept_ra=0

# Disable IPv6 forwarding (if not router)
sysctl -w net.ipv6.conf.all.forwarding=0

# Enable privacy extensions for clients
sysctl -w net.ipv6.conf.all.use_tempaddr=2

# Disable autoconfiguration if using static addressing
sysctl -w net.ipv6.conf.all.autoconf=0

Adoption and Compatibility

Global IPv6 Adoption Statistics (2024)

By Region:

India: 72% IPv6 adoption (Google measurements)
United States: 48% IPv6 adoption
Germany: 55% IPv6 adoption
Brazil: 42% IPv6 adoption
China: 23% IPv6 adoption
Worldwide Average: ~40% IPv6 capability

By Provider Type:

Mobile Networks: 70-90% IPv6 (highest adoption)
Residential ISPs: 40-60% IPv6
Hosting Providers: 50-70% IPv6
CDNs (Major): 85-95% IPv6 (Cloudflare, Akamai, Fastly)
Enterprises: 20-40% IPv6 (slowest adoption)

By Content:

Google: 40% of traffic via IPv6
Facebook: 38% of traffic via IPv6
Cloudflare: 31% of requests via IPv6

Analysis: IPv6 adoption varies dramatically by region and sector. Mobile leads, enterprise lags.

Operating System Support

Modern Operating Systems:

• Linux: Full support since kernel 2.6 (2004)
• Windows: Full support since Windows Vista/Server 2008
• macOS: Full support since OS X 10.7
• iOS/Android: Full support in modern versions

Default Configuration:

• Most OSes enable IPv6 by default
• Dual-stack preferred over IPv4-only
• Privacy extensions enabled on clients

Application Compatibility

Full IPv6 Support:

• Web servers: Apache, Nginx, IIS
• Databases: MySQL, PostgreSQL, MongoDB
• Web browsers: All modern browsers
• Email servers: Postfix, Exim, Exchange
• DNS servers: BIND, Unbound, PowerDNS

Potential Issues:

• Legacy applications may be IPv4-only
• Hardcoded IPv4 addresses in code/config
• Monitoring tools may lack IPv6 support
• Some network equipment older than 2010 may lack full IPv6

Deployment Strategies

IPv4-Only Deployment

When Appropriate:

• Legacy internal networks
• No internet-facing services
• Existing infrastructure (no immediate need)

Limitations:

• Cannot access IPv6-only resources
• Not future-proof
• May require NAT for address conservation

Configuration Example (Linux):

# Disable IPv6
sysctl -w net.ipv6.conf.all.disable_ipv6=1
sysctl -w net.ipv6.conf.default.disable_ipv6=1

IPv6-Only Deployment

When Appropriate:

• Modern cloud environments
• Mobile networks
• Greenfield deployments

Requirements:

• DNS64/NAT64 for IPv4-only services
• All applications must support IPv6

Advantages:

• Simplified network design
• No NAT complexity
• Better performance

Configuration Example (DNS64/NAT64):

# Configure DNS64
# /etc/bind/named.conf.options
dns64 64:ff9b::/96 {
    clients { any; };
};

# NAT64 gateway configuration
# Enable forwarding
sysctl -w net.ipv6.conf.all.forwarding=1

Dual-Stack Deployment (Recommended)

Advantages:

• Full compatibility with both protocols
• Gradual migration path
• Access to all internet resources
• Happy Eyeballs optimization (RFC 6555)

Configuration Example (Linux Server):

/etc/network/interfaces (Debian/Ubuntu):

auto eth0
iface eth0 inet static
    address 192.168.1.100
    netmask 255.255.255.0
    gateway 192.168.1.1
    dns-nameservers 8.8.8.8 1.1.1.1

iface eth0 inet6 static
    address 2001:db8:1234:5678::100
    netmask 64
    gateway 2001:db8:1234:5678::1
    dns-nameservers 2001:4860:4860::8888 2606:4700:4700::1111

/etc/sysconfig/network-scripts/ifcfg-eth0 (RHEL/CentOS):

# IPv4
BOOTPROTO=static
IPADDR=192.168.1.100
PREFIX=24
GATEWAY=192.168.1.1
DNS1=8.8.8.8

# IPv6
IPV6INIT=yes
IPV6ADDR=2001:db8:1234:5678::100/64
IPV6_DEFAULTGW=2001:db8:1234:5678::1
DNS2=2001:4860:4860::8888

Happy Eyeballs (RFC 6555)

How It Works:

1. Client requests both A (IPv4) and AAAA (IPv6) records
2. Attempts IPv6 connection first
3. If IPv6 doesn't respond within 250ms, attempts IPv4 in parallel
4. Uses whichever connects first
5. Prefers IPv6 for future connections if successful

Benefits:

• Seamless fallback
• User doesn't experience delays
• Gradual IPv6 preference as networks improve

Implementation:

• Modern browsers implement Happy Eyeballs
• Applications using getaddrinfo() get automatic support
• Some libraries require explicit dual-stack support

Transition Mechanisms

Tunneling (IPv6 over IPv4)

6to4 (RFC 3056):

• Automatic tunneling using IPv4 infrastructure
• Uses 2002::/16 prefix
• Embeds IPv4 address in IPv6 address
• Status: Deprecated due to reliability issues

Teredo (RFC 4380):

• NAT traversal for IPv6
• Used when behind IPv4 NAT
• Status: Deprecated (Windows phasing out)

6in4 (IPv6-in-IPv4):

• Manual tunnel configuration
• Requires tunnel broker or ISP support
• Example: Hurricane Electric tunnel broker
• Use: Still viable for IPv6 connectivity when ISP lacks native IPv6

Configuration Example (6in4 Tunnel):

# Create tunnel interface
ip tunnel add he-ipv6 mode sit remote 216.66.80.26 local <YOUR_IPV4> ttl 255
ip link set he-ipv6 up
ip addr add 2001:470:1f1c:42::2/64 dev he-ipv6
ip route add ::/0 dev he-ipv6
ip -6 addr

Translation Mechanisms

NAT64/DNS64:

• Translates IPv6 to IPv4 for accessing IPv4-only services
• DNS64 synthesizes AAAA records from A records
• Enables IPv6-only networks to reach IPv4 internet
• Use: Essential for IPv6-only deployments

NAT64 Configuration (Jool):

# Install Jool
apt-get install jool-dkms jool-tools

# Configure NAT64
modprobe jool pool6=64:ff9b::/96
jool instance add "default" --netfilter --pool6 64:ff9b::/96
jool -i "default" pool4 add 192.0.2.1 1-65535

464XLAT:

• CLAT (Customer-side translator) + PLAT (Provider-side translator)
• Enables IPv4 apps on IPv6-only networks
• Used by mobile carriers
• Transparent to applications

Use Case Analysis

IPv4 Optimal Use Cases

1. Legacy Systems and Applications

• Why: May not support IPv6
• Reality: Many enterprise apps IPv4-only
• Example: Old ERP systems, custom applications
• Strategy: Maintain IPv4 support until migration

2. Internal Networks (No Internet Exposure)

• Why: Private addressing sufficient
• Address space: RFC 1918 provides adequate addresses
• Example: Lab networks, test environments
• Note: Still consider dual-stack for future-proofing

3. Simple Home Networks

• Why: ISP may not provide IPv6
• Configuration: Simpler for non-technical users
• Example: Home routers, consumer devices
• Trend: Shifting toward dual-stack as ISPs deploy IPv6

4. Embedded Systems with Limited Resources

• Why: Smaller protocol stack
• Memory: IPv4 stack smaller footprint
• Example: IoT devices with minimal RAM
• Note: Modern IoT increasingly IPv6-capable

IPv6 Optimal Use Cases

1. Mobile Networks

• Why: Address exhaustion, no NAT overhead
• Benefits: End-to-end connectivity, better battery life
• Example: LTE/5G networks
• Reality: Most mobile carriers now IPv6-first

2. IoT Deployments

• Why: Billions of devices need unique addresses
• Scalability: IPv4 address space insufficient
• Example: Smart cities, industrial IoT, connected vehicles
• Future: IPv6 essential for IoT growth

3. New Cloud Deployments

• Why: Modern, scalable, eliminates NAT
• Performance: Better routing, lower latency
• Example: Kubernetes clusters, microservices
• Cloud providers: All major providers support IPv6

4. Global Services with High Traffic

• Why: Better routing, improved performance
• CDN: IPv6-native content delivery
• Example: Streaming services, large-scale SaaS
• Performance: 3-5% latency improvement measured

5. Peer-to-Peer Applications

• Why: End-to-end connectivity without NAT traversal
• Complexity: Eliminates complex NAT hole-punching
• Example: WebRTC, VoIP, file sharing
• Benefit: Simpler application design

6. Data Centers and Enterprise Networks (Greenfield)

• Why: Simplified addressing, future-proof
• Design: No NAT complexity, hierarchical addressing
• Example: New data center builds, cloud regions
• ROI: Operational savings long-term

Dual-Stack Mandatory Use Cases

1. Public-Facing Web Services

• Why: Must support all users (IPv4 and IPv6)
• Compatibility: Maximize reach
• Example: E-commerce sites, SaaS platforms
• Reality: 60% users still IPv4-only in many regions

2. ISP Infrastructure

• Why: Transition period requires both protocols
• Customer support: Mix of IPv4-only and dual-stack customers
• Example: Residential ISP, hosting providers
• Timeline: Dual-stack for 5-15 years minimum

3. Enterprise Networks (Transition)

• Why: Gradual migration from IPv4 to IPv6
• Internal: Legacy apps require IPv4, new apps support IPv6
• Example: Large corporations, universities
• Strategy: Maintain both until all apps migrated

4. Cloud Workloads

• Why: Clients use mix of IPv4 and IPv6
• Load balancers: Dual-stack frontends
• Example: AWS ELB, Google Cloud Load Balancer
• Best practice: Always enable dual-stack for cloud services

Configuration Examples

Web Server Configuration

Apache:

# IPv4-only
<VirtualHost 192.168.1.100:80>
    ServerName example.com
    DocumentRoot /var/www/html
</VirtualHost>

# IPv6-only
<VirtualHost [2001:db8::1]:80>
    ServerName example.com
    DocumentRoot /var/www/html
</VirtualHost>

# Dual-stack (recommended)
<VirtualHost *:80>
    ServerName example.com
    DocumentRoot /var/www/html
</VirtualHost>

Listen 80
Listen [::]:80

Nginx:

server {
    # Dual-stack
    listen 80;
    listen [::]:80;

    server_name example.com;
    root /var/www/html;
}

# IPv6-only example
server {
    listen [::]:80;
    server_name ipv6.example.com;
    root /var/www/ipv6;
}

Database Configuration

MySQL/MariaDB:

# /etc/mysql/my.cnf
[mysqld]
bind-address = 0.0.0.0                  # IPv4 all interfaces
bind-address = ::                       # IPv6 all interfaces (or both)

# Dual-stack: two bind-address directives (MySQL 8.0+)
bind-address = 0.0.0.0,::

PostgreSQL:

# /etc/postgresql/*/main/postgresql.conf
listen_addresses = '*'                  # Both IPv4 and IPv6

# /etc/postgresql/*/main/pg_hba.conf
host    all    all    0.0.0.0/0          md5     # IPv4
host    all    all    ::/0               md5     # IPv6

Firewall Configuration

iptables + ip6tables:

# IPv4 rules (iptables)
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -j DROP

# IPv6 rules (ip6tables)
ip6tables -A INPUT -p tcp --dport 80 -j ACCEPT
ip6tables -A INPUT -p tcp --dport 443 -j ACCEPT
ip6tables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
ip6tables -A INPUT -p ipv6-icmp -j ACCEPT  # Allow ICMPv6 (required)
ip6tables -A INPUT -j DROP

firewalld (dual-stack default):

# firewalld handles both IPv4 and IPv6 automatically
firewall-cmd --permanent --add-service=http
firewall-cmd --permanent --add-service=https
firewall-cmd --reload

# IPv6-specific rules
firewall-cmd --permanent --add-rich-rule='rule family="ipv6" source address="2001:db8::/32" accept'

Troubleshooting

IPv6 Connectivity Testing

# Check IPv6 address configuration
ip -6 addr show

# Test IPv6 connectivity
ping6 google.com
ping6 2001:4860:4860::8888  # Google DNS

# Traceroute IPv6
traceroute6 google.com

# Test dual-stack preference
curl -6 https://ipv6.google.com  # Force IPv6
curl -4 https://google.com       # Force IPv4

# Check IPv6 default route
ip -6 route show

Common IPv6 Issues

Issue 1: No IPv6 Address

# Check if IPv6 enabled
sysctl net.ipv6.conf.all.disable_ipv6
# Should return 0 (enabled)

# Enable if disabled
sysctl -w net.ipv6.conf.all.disable_ipv6=0

# Check for SLAAC
ip -6 addr show | grep "scope global"
# Should see global IPv6 address

Issue 2: IPv6 Routing Problems

# Check default gateway
ip -6 route show | grep default
# Should show: default via fe80::... dev eth0

# Manually add default route if missing
ip -6 route add default via fe80::1 dev eth0

Issue 3: Firewall Blocking IPv6

# Check ip6tables rules
ip6tables -L -n -v

# Temporarily flush to test
ip6tables -F
ip6tables -X

# Ensure ICMPv6 allowed (required for IPv6)
ip6tables -A INPUT -p ipv6-icmp -j ACCEPT

Decision Framework

Choose IPv4-Only When:

Temporary/Legacy:

• Legacy systems cannot support IPv6
• Internal network with no external requirements
• Short-term deployment (<2 years)
• ISP doesn't provide IPv6

Not Recommended For:

• New production deployments
• Internet-facing services
• Long-term infrastructure

Choose IPv6-Only When:

Modern Environments:

• Greenfield mobile network
• Modern cloud-native application
• All dependencies support IPv6
• DNS64/NAT64 available for IPv4 resources

Requirements:

• All services IPv6-capable
• DNS64/NAT64 for legacy IPv4
• User base primarily IPv6
• Cloud provider supports IPv6

Choose Dual-Stack When: (Recommended for Most Cases)

Universal Compatibility:

• Public-facing web services
• Enterprise production networks
• ISP infrastructure
• Any service requiring broad compatibility

Advantages:

• Maximum compatibility
• Gradual migration path
• Future-proof
• No complex translation needed

Timeline:

• Maintain dual-stack 5-15 years minimum
• Transition period for internet likely 10-20+ years
• Eventually IPv6-only future

Conclusion

IPv6 is the future of internet addressing, but IPv4 remains dominant in many environments. The optimal strategy for most organizations is dual-stack deployment, ensuring compatibility with both protocols while gradually transitioning to IPv6-primary operations.

Key Recommendations:

1. For new deployments:

• Implement dual-stack from day one
• Design with IPv6 as primary
• Ensure all services IPv6-capable

2. For existing IPv4 infrastructure:

• Add IPv6 alongside IPv4 (dual-stack)
• Test applications for IPv6 compatibility
• Gradual migration, no "flag day" switch

3. For internet-facing services:

• Dual-stack mandatory
• Monitor IPv6 traffic percentage
• Optimize for IPv6 (it's faster)

4. For ISPs and hosting providers:

• Provide IPv6 to all customers
• Implement CGN for IPv4 (temporary)
• Educate customers on IPv6 benefits

5. For enterprise networks:

• Enable IPv6 on infrastructure
• Test applications systematically
• Maintain dual-stack for foreseeable future

Timeline Expectations:

• Short-term (2024-2030): Dual-stack dominant
• Medium-term (2030-2040): IPv6 majority, IPv4 legacy
• Long-term (2040+): IPv6-primary, IPv4 compatibility mode

IPv6 adoption is inevitable and accelerating. The question is not "if" but "when" and "how fast." Organizations that embrace dual-stack now position themselves for smoother transition and better performance as the internet continues its evolution to IPv6. Delaying IPv6 deployment only increases future migration complexity and costs.