Lately I've been spending a lot of time on projects related to migrating traditional MPLS (based on LDP) to a new solution based on MPLS Segment Routing. Migrations can be challenging and very interesting, so I’ll try to illustrate, using the example of several clients – of course, the data will be anonymized – what the migration process looks like and what its main advantages are. I'm returning to running this blog because it gives me the motivation for further activities and learning. I hope there will be readers for what I share here and that it will be useful to someone.

Reflecting on the value of CCIE and how it opened opportunities

 

Just wanted to come back to write this blog. I have been a CCIE for a few years now and wanted to share with you how many doors and opportunities it has opened for me. I am currently trying to motivate myself to study for the CCDE and focus on the world of AI, which is increasingly fascinating to me.

First, I asked AI for its current opinion on CCIE and CCDE. It seems that it's still worth going on this journey and focusing on learning.

That's why I will be posting various summaries from the world of Networking and AI here.

 

The CCIE (Cisco Certified Internetwork Expert) and CCDE (Cisco Certified Design Expert) certifications are among the most prestigious credentials in the IT industry, offering a wide range of technical and career opportunities. Here’s a deeper look at what they bring to the table:

CCIE (Cisco Certified Internetwork Expert):

1. Advanced Technical Expertise:

   • The CCIE certification validates your ability to design, implement, and troubleshoot complex network infrastructures.

   • It covers advanced topics such as routing and switching (CCIE Enterprise), data center technologies, security, service provider, and wireless networks.

   • You’ll gain hands-on experience with cutting-edge Cisco technologies, including SD-WAN, automation, and network programmability.

2. Career Growth:

   • Opens doors to high-level roles such as Senior Network Engineer, Network Architect, or Technical Consultant.

   • Employers value CCIE-certified professionals for their ability to solve complex network challenges and optimize performance.

3. Global Recognition:

   • CCIE is globally recognized as a gold standard in networking expertise, giving you credibility and respect in the industry.

4. Salary Potential:

   • CCIE-certified professionals often command higher salaries due to their specialized skills and ability to handle mission-critical networks.

5. Personal Satisfaction:

   • Achieving CCIE is a challenging but rewarding journey that brings a deep sense of accomplishment and confidence in your technical abilities.

---

CCDE (Cisco Certified Design Expert):

1. Network Design Mastery:

   • The CCDE certification focuses on advanced network design principles, enabling you to create scalable, secure, and efficient network architectures.

   • It emphasizes strategic thinking, including business requirements, technical constraints, and risk management.

   • You’ll learn to design solutions for large-scale networks, integrating technologies like MPLS, QoS, and cloud connectivity.

2. Strategic Roles:

   • Prepares you for roles such as Network Design Architect, Solutions Architect, or Technical Lead.

   • You’ll be responsible for designing networks that align with business goals and future-proof organizations.

3. Global Impact:

   • CCDE is recognized worldwide as a mark of excellence in network design, making you a sought-after expert for global projects.

4. Salary Potential:

   • CCDE-certified professionals often earn top-tier salaries due to their ability to design innovative and cost-effective solutions.

5. Personal Satisfaction:

   • Earning the CCDE certification is a testament to your ability to think strategically and solve complex design challenges, bringing immense professional pride.

---

Why Pursue CCIE or CCDE?

• Technical Mastery: Both certifications push you to the forefront of networking technology, giving you the skills to work with the latest tools and methodologies.

• Career Advancement: They open doors to leadership roles, consulting opportunities, and high-impact projects.

• Global Opportunities: With these certifications, you can work anywhere in the world, as they are recognized and respected across industries.

• Personal Growth: The rigorous preparation process is intellectually stimulating and builds resilience, problem-solving skills, and confidence.

• Community and Recognition: Joining the elite group of CCIE and CCDE holders connects you with a global network of experts and thought leaders.

---

Conclusion:

Pursuing CCIE or CCDE is not just about earning a certification—it’s about transforming your career and becoming a leader in the networking field. The journey is demanding, but the rewards are immense: technical mastery, career growth, global recognition, and personal satisfaction. If you’re passionate about networking and ready to take your skills to the next level, CCIE and CCDE are the ultimate goals to strive for. They don’t just validate your expertise—they redefine what you’re capable of achieving.

Why Migrate from MPLS to Segment Routing?

 

Why Migrate from MPLS to Segment Routing? A Comprehensive Guide

In today’s rapidly evolving networking landscape, enterprises face the constant challenge of optimizing their network infrastructure to meet growing demands for performance, scalability, and flexibility. One of the key trends in recent years is the migration from traditional MPLS (Multiprotocol Label Switching) to modern technologies like Segment Routing (SR). In this article, we will explore why migrating from MPLS to Segment Routing is a strategic move, the benefits it offers, and a detailed overview of the migration process from LDP (Label Distribution Protocol) to SR.

 

Why Migrate from MPLS to Segment Routing?

1. Simplified Network Architecture

MPLS, while effective, requires complex configuration and management, especially in large-scale networks. Segment Routing simplifies network architecture by eliminating the need for additional protocols like LDP or RSVP-TE (Resource Reservation Protocol - Traffic Engineering). In SR, path information is encoded directly in packet headers, reducing the number of protocols and management mechanisms.

2. Improved Scalability

Segment Routing offers better scalability compared to MPLS. In traditional MPLS networks, each router must maintain the state of every label for every path, which can lead to significant memory and CPU overhead in large networks. SR stores path information more efficiently, enabling easier network scaling without requiring additional hardware resources.

3. Enhanced Traffic Control and Flexibility

SR provides greater flexibility in traffic engineering. By allowing administrators to define application-specific paths (segments), SR enables precise control over how traffic flows through the network. This is particularly useful for applications requiring high availability, such as cloud services or business-critical applications.

4. Seamless Integration with SDN (Software-Defined Networking)

Segment Routing is inherently compatible with SDN architectures, enabling greater automation and optimization. By integrating with SDN controllers, SR allows for dynamic traffic management, automatic fault detection, and fast rerouting, resulting in higher network availability and reliability.

5. Cost Reduction

Migrating to Segment Routing can lead to significant cost savings. The simplified architecture and reduced management requirements mean IT teams can operate more efficiently, and the costs associated with network maintenance can be significantly reduced. Additionally, SR can operate on existing MPLS infrastructure, allowing for a gradual migration without the need for immediate hardware upgrades.

6. Support for Modern Applications

In the era of digital transformation, enterprises are increasingly deploying modern applications such as IoT (Internet of Things), AI (Artificial Intelligence), and cloud-based services. Segment Routing is better suited to meet the demands of these applications, offering lower latency, higher throughput, and improved traffic control.

7. Easier Inter-Domain Traffic Management

For wide-area networks (WANs) or service provider networks, SR simplifies inter-domain traffic management. By enabling end-to-end path definition, SR allows for more efficient traffic management across different network domains, which is particularly important for large enterprises and telecom operators.

8. Future-Proofing with IPv6 Support

Segment Routing is designed with the future in mind, including full support for IPv6. As more organizations transition to IPv6, SR ensures a smooth migration and integration with new networking standards.

---

The Migration Process: From LDP to Segment Routing

Migrating from LDP-based MPLS to Segment Routing requires careful planning and execution. Below is a step-by-step guide to ensure a smooth transition:

1. Assess Your Current Network

• Inventory Your Network: Document all devices, links, and configurations in your MPLS network.

• Identify Dependencies: Determine which applications and services rely on LDP and MPLS.

• Evaluate Hardware and Software Compatibility: Ensure your network devices support Segment Routing. Most modern routers and switches support SR, but older hardware may require upgrades.

2. Design the Segment Routing Architecture

• Define Segment Routing Domains: Decide where SR will be implemented (e.g., core, edge, or entire network).

• Plan Segment Identifiers (SIDs): Allocate Node SIDs, Adjacency SIDs, and any other required SIDs.

• Design Traffic Engineering Policies: Define how traffic will be steered using SR policies, especially for critical applications.

3. Configure Segment Routing

• Enable SR on Devices: Configure SR on routers and switches, ensuring compatibility with existing MPLS infrastructure.

• Configure IGP (Interior Gateway Protocol): Use protocols like OSPF or IS-IS to distribute SIDs and SR information.

• Implement SR Policies: Define and deploy SR policies for traffic engineering and path optimization.

4. Test the SR Configuration

• Conduct Lab Testing: Test the SR configuration in a lab environment to validate functionality and performance.

• Simulate Failures: Test fault tolerance and rerouting capabilities to ensure network resilience.

• Verify Interoperability: Ensure SR works seamlessly with existing MPLS and LDP configurations.

5. Gradually Migrate Traffic

• Start with Non-Critical Traffic: Begin by migrating less critical traffic to SR to minimize risk.

• Monitor Performance: Use network monitoring tools to track performance and identify any issues.

• Migrate Critical Traffic: Once the SR network is stable, migrate critical applications and services.

6. Decommission LDP

• Disable LDP on Devices: Once all traffic has been migrated to SR, disable LDP on routers and switches.

• Remove LDP Configurations: Clean up any remaining LDP configurations to simplify the network.

7. Optimize and Maintain

• Fine-Tune SR Policies: Continuously optimize SR policies based on network performance and traffic patterns.

• Monitor and Troubleshoot: Use monitoring tools to proactively identify and resolve issues.

• Train Your Team: Ensure your network team is trained on Segment Routing concepts and management.

---

Key Considerations During Migration

• Phased Approach: A gradual migration reduces risk and allows for thorough testing at each stage.

• Backup and Rollback Plans: Always have a rollback plan in case of unexpected issues during migration.

• Vendor Support: Work closely with your hardware and software vendors to ensure compatibility and resolve any issues.

• Documentation: Keep detailed documentation of the migration process, configurations, and changes for future reference.

---

Conclusion

Migrating from MPLS to Segment Routing is a strategic decision that can bring significant benefits to your organization, including simplified architecture, improved scalability, enhanced traffic control, and cost savings. The migration process, particularly from LDP to SR, requires careful planning, testing, and execution, but the long-term advantages far outweigh the initial effort.

By adopting Segment Routing, your organization can build a more efficient, flexible, and future-proof network capable of meeting the demands of modern applications and digital transformation. If you’re considering this migration, consult with networking experts to develop a tailored strategy that ensures a smooth and successful transition.

 

Segment Routing vs. Traditional MPLS: A Modern Approach to Traffic Engineering

 

1. Introduction

Modern networks strive for greater efficiency, simpler management, and enhanced flexibility. Segment Routing (SR) has emerged as a powerful alternative to traditional MPLS (Multiprotocol Label Switching), eliminating many of its limitations, such as reliance on Label Distribution Protocol (LDP) and RSVP-TE for signaling. This article compares SR-MPLS with classical MPLS and explores its key advantages, including a step-by-step migration process illustrated with network diagrams.

---

2. Traditional MPLS and Its Limitations

MPLS uses labels for efficient packet forwarding, relying on LDP for label distribution or RSVP-TE for traffic engineering. While MPLS has served networks well, it faces challenges in scalability and complexity.

Limitations of MPLS:

• LDP dependency: A separate protocol for label distribution, increasing overhead.

• No native ECMP support: RSVP-TE lacks equal-cost multipath (ECMP) forwarding.

• Complex control plane: Each router must maintain LDP sessions, increasing memory and processing requirements.

• Traffic engineering challenges: Requires additional mechanisms such as RSVP-TE or centralized SDN controllers.

---

3. Segment Routing: A Modern Alternative

Segment Routing (SR-MPLS) simplifies network design by encoding the forwarding path within the packet itself using Segment Identifiers (SIDs). Instead of relying on LDP, SR uses existing IGP (OSPF/IS-IS) extensions to distribute labels.

Advantages of SR:

• No need for LDP: Simplifies the control plane.

• Uses IGP for label distribution: Eliminates additional protocols.

• Stateless core: Reduces memory and processing overhead on routers.

• Better traffic engineering: Native support for SR-TE (Segment Routing Traffic Engineering).

• Built-in ECMP: Efficient utilization of available paths.

---

4. Migration from MPLS-LDP to Segment Routing

Migration to SR is typically done in phases to minimize service disruption. The following sections illustrate this transition with network diagrams.

4.1 Initial State: MPLS Network with LDP

In this stage, the network is fully MPLS-based, with LDP used for label distribution.

(Image: Traditional MPLS Network with LDP)

4.2 Hybrid State: Coexistence of LDP and SR

During migration, both LDP and SR run in parallel, allowing gradual migration of routers to SR.

(Image: Hybrid Network with MPLS-LDP and Segment Routing)

4.3 Fully Migrated State: Pure SR-MPLS Network

Once all routers support SR, LDP is removed, simplifying the network architecture.

(Image: Fully Migrated Segment Routing Network)

---

5. Configuration Examples

5.1 MPLS-LDP Configuration (Traditional Approach)

router isis 1
 net 49.0001.0000.0000.0001.00
 is-type level-2
 metric-style wide

mpls ip
mpls label protocol ldp
interface GigabitEthernet0/0/0
 mpls ip
 mpls ldp

router ldp
 mpls ldp router-id Loopback0 force

5.2 Segment Routing Configuration

router isis 1
 net 49.0001.0000.0000.0001.00
 is-type level-2
 metric-style wide
 segment-routing mpls

interface GigabitEthernet0/0/0
 ip router isis 1

segment-routing
 mpls
  set srgb 16000 23999
  node-sid 16001

---

6. Conclusion

Segment Routing provides a more scalable, flexible, and efficient alternative to traditional MPLS-LDP. By eliminating LDP and RSVP-TE, SR-MPLS simplifies operations, reduces control plane overhead, and enables advanced traffic engineering. Migrating to SR can be done in phases to ensure smooth adoption without disrupting services.

Data Center Notes

http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Data_Center/VMDC/2-6/vmdcm1f1wp.html

http://dustydev.blogspot.com/2013/03/data-center-design-constraints.html

http://dustydev.blogspot.fr/2013/08/cisco-nexus-7000-proxy-routing.html

DHCP Options

This post and the next one with ICMP types I am using as a usefull notes and I only share this to have quick access to RFC links.

Source info => IANA

DHCP OPTION FIELD :

Tag	Name	Desription	RFC
0	Pad	None	[RFC2132]
1	Subnet Mask	Subnet Mask Value	[RFC2132]
2	Time Offset	Time Offset in Seconds from UTC (note: deprecated by 100 and 101)	[RFC2132]
3	Router	N/4 Router addresses	[RFC2132]
4	Time Server	N/4 Timeserver addresses	[RFC2132]
5	Name Server	N/4 IEN-116 Server addresses	[RFC2132]
6	Domain Server	N/4 DNS Server addresses	[RFC2132]
7	Log Server	N/4 Logging Server addresses	[RFC2132]
8	Quotes Server	N/4 Quotes Server addresses	[RFC2132]
9	LPR Server	N/4 Printer Server addresses	[RFC2132]
10	Impress Server	N/4 Impress Server addresses	[RFC2132]
11	RLP Server	N/4 RLP Server addresses	[RFC2132]
12	Hostname	Hostname string	[RFC2132]
13	Boot File Size	Size of boot file in 512 byte chunks	[RFC2132]
14	Merit Dump File	Client to dump and name the file to dump it to	[RFC2132]
15	Domain Name	The DNS domain name of the client	[RFC2132]
16	Swap Server	Swap Server address	[RFC2132]
17	Root Path	Path name for root disk	[RFC2132]
18	Extension File	Path name for more BOOTP info	[RFC2132]
19	Forward On/Off	Enable/Disable IP Forwarding	[RFC2132]
20	SrcRte On/Off	Enable/Disable Source Routing	[RFC2132]
21	Policy Filter	Routing Policy Filters	[RFC2132]
22	Max DG Assembly	Max Datagram Reassembly Size	[RFC2132]
23	Default IP TTL	Default IP Time to Live	[RFC2132]
24	MTU Timeout	Path MTU Aging Timeout	[RFC2132]
25	MTU Plateau	Path MTU Plateau Table	[RFC2132]
26	MTU Interface	Interface MTU Size	[RFC2132]
27	MTU Subnet	All Subnets are Local	[RFC2132]
28	Broadcast Address	Broadcast Address	[RFC2132]
29	Mask Discovery	Perform Mask Discovery	[RFC2132]
30	Mask Supplier	Provide Mask to Others	[RFC2132]
31	Router Discovery	Perform Router Discovery	[RFC2132]
32	Router Request	Router Solicitation Address	[RFC2132]
33	Static Route	Static Routing Table	[RFC2132]
34	Trailers	Trailer Encapsulation	[RFC2132]
35	ARP Timeout	ARP Cache Timeout	[RFC2132]
36	Ethernet	Ethernet Encapsulation	[RFC2132]
37	Default TCP TTL	Default TCP Time to Live	[RFC2132]
38	Keepalive Time	TCP Keepalive Interval	[RFC2132]
39	Keepalive Data	TCP Keepalive Garbage	[RFC2132]
40	NIS Domain	NIS Domain Name	[RFC2132]
41	NIS Servers	NIS Server Addresses	[RFC2132]
42	NTP Servers	NTP Server Addresses	[RFC2132]
43	Vendor Specific	Vendor Specific Information	[RFC2132]
44	NETBIOS Name Srv	NETBIOS Name Servers	[RFC2132]
45	NETBIOS Dist Srv	NETBIOS Datagram Distribution	[RFC2132]
46	NETBIOS Node Type	NETBIOS Node Type	[RFC2132]
47	NETBIOS Scope	NETBIOS Scope	[RFC2132]
48	X Window Font	X Window Font Server	[RFC2132]
49	X Window Manager	X Window Display Manager	[RFC2132]
50	Address Request	Requested IP Address	[RFC2132]
51	Address Time	IP Address Lease Time	[RFC2132]
52	Overload	Overload "sname" or "file"	[RFC2132]
53	DHCP Msg Type	DHCP Message Type	[RFC2132]
54	DHCP Server Id	DHCP Server Identification	[RFC2132]
55	Parameter List	Parameter Request List	[RFC2132]
56	DHCP Message	DHCP Error Message	[RFC2132]
57	DHCP Max Msg Size	DHCP Maximum Message Size	[RFC2132]
58	Renewal Time	DHCP Renewal (T1) Time	[RFC2132]
59	Rebinding Time	DHCP Rebinding (T2) Time	[RFC2132]
60	Class Id	Class Identifier	[RFC2132]
61	Client Id	Client Identifier	[RFC2132]
62	NetWare/IP Domain	NetWare/IP Domain Name	[RFC2242]
63	NetWare/IP Option	NetWare/IP sub Options	[RFC2242]
64	NIS-Domain-Name	NIS+ v3 Client Domain Name	[RFC2132]
65	NIS-Server-Addr	NIS+ v3 Server Addresses	[RFC2132]
66	Server-Name	TFTP Server Name	[RFC2132]
67	Bootfile-Name	Boot File Name	[RFC2132]
68	Home-Agent-Addrs	Home Agent Addresses	[RFC2132]
69	SMTP-Server	Simple Mail Server Addresses	[RFC2132]
70	POP3-Server	Post Office Server Addresses	[RFC2132]
71	NNTP-Server	Network News Server Addresses	[RFC2132]
72	WWW-Server	WWW Server Addresses	[RFC2132]
73	Finger-Server	Finger Server Addresses	[RFC2132]
74	IRC-Server	Chat Server Addresses	[RFC2132]
75	StreetTalk-Server	StreetTalk Server Addresses	[RFC2132]
76	STDA-Server	ST Directory Assist. Addresses	[RFC2132]
77	User-Class	User Class Information	[RFC3004]
78	Directory Agent	directory agent information	[RFC2610]
79	Service Scope	service location agent scope	[RFC2610]
80	Rapid Commit	Rapid Commit	[RFC4039]
81	Client FQDN	Fully Qualified Domain Name	[RFC4702]
82	Relay Agent Information	Relay Agent Information	[RFC3046]
83	iSNS	Internet Storage Name Service	[RFC4174]
84	REMOVED/Unassigned		[RFC3679]
85	NDS Servers	Novell Directory Services	[RFC2241]
86	NDS Tree Name	Novell Directory Services	[RFC2241]
87	NDS Context	Novell Directory Services	[RFC2241]
88	BCMCS Controller Domain Name list		[RFC4280]
89	BCMCS Controller IPv4 address option		[RFC4280]
90	Authentication	Authentication	[RFC3118]
91	client-last-transaction-time option		[RFC4388]
92	associated-ip option		[RFC4388]
93	Client System	Client System Architecture	[RFC4578]
94	Client NDI	Client Network Device Interface	[RFC4578]
95	LDAP	Lightweight Directory Access Protocol	[RFC3679]
96	REMOVED/Unassigned		[RFC3679]
97	UUID/GUID	UUID/GUID-based Client Identifier	[RFC4578]
98	User-Auth	Open Group's User Authentication	[RFC2485]
99	GEOCONF_CIVIC		[RFC4776]
100	PCode	IEEE 1003.1 TZ String	[RFC4833]
101	TCode	Reference to the TZ Database	[RFC4833]
102-107	REMOVED/Unassigned		[RFC3679]
108	REMOVED/Unassigned		[RFC3679]
109	Unassigned		[RFC3679]
110	REMOVED/Unassigned		[RFC3679]
111	Unassigned		[RFC3679]
112	Netinfo Address	NetInfo Parent Server Address	[RFC3679]
113	Netinfo Tag	NetInfo Parent Server Tag	[RFC3679]
114	URL	URL	[RFC3679]
115	REMOVED/Unassigned		[RFC3679]
116	Auto-Config	DHCP Auto-Configuration	[RFC2563]
117	Name Service Search	Name Service Search	[RFC2937]
118	Subnet Selection Option	Subnet Selection Option	[RFC3011]
119	Domain Search	DNS domain search list	[RFC3397]
120	SIP Servers DHCP Option	SIP Servers DHCP Option	[RFC3361]
121	Classless Static Route Option	Classless Static Route Option	[RFC3442]
122	CCC	CableLabs Client Configuration	[RFC3495]
123	GeoConf Option	GeoConf Option	[RFC6225]
124	V-I Vendor Class	Vendor-Identifying Vendor Class	[RFC3925]
125	V-I Vendor-Specific Information	Vendor-Identifying Vendor-Specific Information	[RFC3925]
126	Removed/Unassigned		[RFC3679]
127	Removed/Unassigned		[RFC3679]
128	PXE - undefined (vendor specific)		[RFC4578]
128	Etherboot signature. 6 bytes: E4:45:74:68:00:00
128	DOCSIS "full security" server IP address
128	TFTP Server IP address (for IP Phone software load)
129	PXE - undefined (vendor specific)		[RFC4578]
129	Kernel options. Variable length string
129	Call Server IP address
130	PXE - undefined (vendor specific)		[RFC4578]
130	Ethernet interface. Variable length string.
130	Discrimination string (to identify vendor)
131	PXE - undefined (vendor specific)		[RFC4578]
131	Remote statistics server IP address
132	PXE - undefined (vendor specific)		[RFC4578]
132	IEEE 802.1Q VLAN ID
133	PXE - undefined (vendor specific)		[RFC4578]
133	IEEE 802.1D/p Layer 2 Priority
134	PXE - undefined (vendor specific)		[RFC4578]
134	Diffserv Code Point (DSCP) for VoIP signalling and media streams
135	PXE - undefined (vendor specific)		[RFC4578]
135	HTTP Proxy for phone-specific applications
136	OPTION_PANA_AGENT		[RFC5192]
137	OPTION_V4_LOST		[RFC5223]
138	OPTION_CAPWAP_AC_V4	CAPWAP Access Controller addresses	[RFC5417]
139	OPTION-IPv4_Address-MoS	a series of suboptions	[RFC5678]
140	OPTION-IPv4_FQDN-MoS	a series of suboptions	[RFC5678]
141	SIP UA Configuration Service Domains	List of domain names to search for SIP User Agent Configuration	[RFC6011]
142	OPTION-IPv4_Address-ANDSF	ANDSF IPv4 Address Option for DHCPv4	[RFC6153]
143	Unassigned
144	GeoLoc	Geospatial Location with Uncertainty	[RFC6225]
145	FORCERENEW_NONCE_CAPABLE	Forcerenew Nonce Capable	[RFC6704]
146	RDNSS Selection	Information for selecting RDNSS	[RFC6731]
147-149	Unassigned		[RFC3942]
150	TFTP server address		[RFC5859]
150	Etherboot
150	GRUB configuration path name
151	status-code	Status code and optional N byte text message describing status.	[RFC6926]
152	base-time	Absolute time (seconds since Jan 1, 1970) message was sent.	[RFC6926]
153	start-time-of-state	Number of seconds in the past when client entered current state.	[RFC6926]
154	query-start-time	Absolute time (seconds since Jan 1, 1970) for beginning of query.	[RFC6926]
155	query-end-time	Absolute time (seconds since Jan 1, 1970) for end of query.	[RFC6926]
156	dhcp-state	State of IP address.	[RFC6926]
157	data-source	Indicates information came from local or remote server.	[RFC6926]
158	OPTION_V4_PCP_SERVER	Includes one or multiple lists of PCP server IP addresses; each list is treated as a separate PCP server.	[RFC7291]
159	OPTION_V4_PORTPARAMS	This option is used to configure a set of ports bound to a shared IPv4 address.	[RFC7618]
160	DHCP Captive-Portal	DHCP Captive-Portal	[RFC7710]
161-174	Unassigned		[RFC3942]
175	Etherboot (Tentatively Assigned - 2005-06-23)
176	IP Telephone (Tentatively Assigned - 2005-06-23)
177	Etherboot (Tentatively Assigned - 2005-06-23)
177	PacketCable and CableHome (replaced by 122)
178-207	Unassigned		[RFC3942]
208	PXELINUX Magic	magic string = F1:00:74:7E	[RFC5071][Deprecated]
209	Configuration File	Configuration file	[RFC5071]
210	Path Prefix	Path Prefix Option	[RFC5071]
211	Reboot Time	Reboot Time	[RFC5071]
212	OPTION_6RD	OPTION_6RD with N/4 6rd BR addresses	[RFC5969]
213	OPTION_V4_ACCESS_DOMAIN	Access Network Domain Name	[RFC5986]
214-219	Unassigned
220	Subnet Allocation Option	Subnet Allocation Option	[RFC6656]
221	Virtual Subnet Selection (VSS) Option		[RFC6607]
222-223	Unassigned		[RFC3942]
224-254	Reserved (Private Use)
255	End	None	[RFC2132]